obs-studio UI: Implement stream settings UI

- Updated the services API so that it links up with an output and
   the output gets data from that service rather than via settings.
   This allows the service context to have control over how an output is
   used, and makes it so that the URL/key/etc isn't necessarily some
   static setting.

   Also, if the service is attached to an output, it will stick around
   until the output is destroyed.

 - The settings interface has been updated so that it can allow the
   usage of service plugins.  What this means is that now you can create
   a service plugin that can control aspects of the stream, and it
   allows each service to create their own user interface if they create
   a service plugin module.

 - Testing out saving of current service information.  Saves/loads from
   JSON in to obs_data_t, seems to be working quite nicely, and the
   service object information is saved/preserved on exit, and loaded
   again on startup.

 - I agonized over the settings user interface for days, and eventually
   I just decided that the only way that users weren't going to be
   fumbling over options was to split up the settings in to simple/basic
   output, pre-configured, and then advanced for advanced use (such as
   multiple outputs or services, which I'll implement later).

   This was particularly painful to really design right, I wanted more
   features and wanted to include everything in one interface but
   ultimately just realized from experience that users are just not
   technically knowledgable about it and will end up fumbling with the
   settings rather than getting things done.

   Basically, what this means is that casual users only have to enter in
   about 3 things to configure their stream:  Stream key, audio bitrate,
   and video bitrate.  I am really happy with this interface for those
   types of users, but it definitely won't be sufficient for advanced
   usage or for custom outputs, so that stuff will have to be separated.

 - Improved the JSON usage for the 'common streaming services' context,
   I realized that JSON arrays are there to ensure sorting, while
   forgetting that general items are optimized for hashing.  So
   basically I'm just using arrays now to sort items in it.

libobs/obs.h

@@ -288,6 +288,10 @@ EXPORT void obs_enum_outputs(bool (*enum_proc)(void*, obs_output_t),
 EXPORT void obs_enum_encoders(bool (*enum_proc)(void*, obs_encoder_t),
 		void *param);
 
+/** Enumerates encoders */
+EXPORT void obs_enum_services(bool (*enum_proc)(void*, obs_service_t),
+		void *param);
+
 /**
  * Gets a source by its name.
  *
@@ -296,6 +300,15 @@ EXPORT void obs_enum_encoders(bool (*enum_proc)(void*, obs_encoder_t),
  */
 EXPORT obs_source_t obs_get_source_by_name(const char *name);
 
+/** Gets an output by its name. */
+EXPORT obs_output_t obs_get_output_by_name(const char *name);
+
+/** Gets an encoder by its name. */
+EXPORT obs_encoder_t obs_get_encoder_by_name(const char *name);
+
+/** Gets an service by its name. */
+EXPORT obs_service_t obs_get_service_by_name(const char *name);
+
 /**
  * Returns the location of a plugin data file.
  *
@@ -737,6 +750,12 @@ EXPORT obs_encoder_t obs_output_get_video_encoder(obs_output_t output);
 /** Returns the current audio encoder associated with this output */
 EXPORT obs_encoder_t obs_output_get_audio_encoder(obs_output_t output);
 
+/** Sets the current service associated with this output. */
+EXPORT void obs_output_set_service(obs_output_t output, obs_service_t service);
+
+/** Gets the current service associated with this output. */
+EXPORT obs_service_t obs_output_get_service(obs_output_t output);
+
 /* ------------------------------------------------------------------------- */
 /* Functions used by outputs */
 
@@ -793,11 +812,10 @@ EXPORT const char *obs_encoder_getdisplayname(const char *id,
  * @param  id        Video encoder ID
  * @param  name      Name to assign to this context
  * @param  settings  Settings
- * @param  video     Video output context to encode data from
  * @return           The video encoder context, or NULL if failed or not found.
  */
 EXPORT obs_encoder_t obs_video_encoder_create(const char *id, const char *name,
-		obs_data_t settings, video_t video);
+		obs_data_t settings);
 
 /**
  * Creates an audio encoder context
@@ -805,11 +823,10 @@ EXPORT obs_encoder_t obs_video_encoder_create(const char *id, const char *name,
  * @param  id        Audio Encoder ID
  * @param  name      Name to assign to this context
  * @param  settings  Settings
- * @param  audio     Audio output context to encode data from
  * @return           The video encoder context, or NULL if failed or not found.
  */
 EXPORT obs_encoder_t obs_audio_encoder_create(const char *id, const char *name,
-		obs_data_t settings, audio_t audio);
+		obs_data_t settings);
 
 /** Destroys an encoder context */
 EXPORT void obs_encoder_destroy(obs_encoder_t encoder);
@@ -844,6 +861,12 @@ EXPORT bool obs_encoder_get_extra_data(obs_encoder_t encoder,
 /** Returns the current settings for this encoder */
 EXPORT obs_data_t obs_encoder_get_settings(obs_encoder_t encoder);
 
+/** Sets the video output context to be used with this encoder */
+EXPORT void obs_encoder_set_video(obs_encoder_t encoder, video_t video);
+
+/** Sets the audio output context to be used with this encoder */
+EXPORT void obs_encoder_set_audio(obs_encoder_t encoder, audio_t audio);
+
 /**
  * Returns the video output context used with this encoder, or NULL if not
  * a video context
@@ -873,6 +896,8 @@ EXPORT obs_service_t obs_service_create(const char *id, const char *name,
 		obs_data_t settings);
 EXPORT void obs_service_destroy(obs_service_t service);
 
+EXPORT const char *obs_service_getname(obs_service_t service);
+
 /** Gets the default settings for a service */
 EXPORT obs_data_t obs_service_defaults(const char *id);
 
@@ -887,11 +912,26 @@ EXPORT obs_properties_t obs_get_service_properties(const char *id,
 EXPORT obs_properties_t obs_service_properties(obs_service_t service,
 		const char *locale);
 
+/** Gets the service type */
+EXPORT const char *obs_service_gettype(obs_service_t service);
+
+/** Updates the settings of the service context */
+EXPORT void obs_service_update(obs_service_t service, obs_data_t settings);
+
+/** Returns the current settings for this service */
+EXPORT obs_data_t obs_service_get_settings(obs_service_t service);
+
 /** Returns the URL for this service context */
-const char *obs_service_get_url(obs_service_t service);
+EXPORT const char *obs_service_get_url(obs_service_t service);
 
 /** Returns the stream key (if any) for this service context */
-const char *obs_service_get_key(obs_service_t service);
+EXPORT const char *obs_service_get_key(obs_service_t service);
+
+/** Returns the username (if any) for this service context */
+EXPORT const char *obs_service_get_username(obs_service_t service);
+
+/** Returns the password (if any) for this service context */
+EXPORT const char *obs_service_get_password(obs_service_t service);
 
 
 /* ------------------------------------------------------------------------- */