(API Change) Refactor module handling

Changed API:
- char *obs_find_plugin_file(const char *sub_path);

  Changed to: char *obs_module_file(const char *file);

  Cahnge it so you no longer need to specify a sub-path such as:
  obs_find_plugin_file("module_name/file.ext")

  Instead, now automatically handle the module data path so all you need
  to do is:
  obs_module_file("file.ext")

- int obs_load_module(const char *name);

  Changed to: int obs_open_module(obs_module_t *module,
                                  const char *path,
                                  const char *data_path);
              bool obs_init_module(obs_module_t module);

  Change the module loading API so that if the front-end chooses, it can
  load modules directly from a specified path, and associate a data
  directory with it on the spot.

  The module will not be initialized immediately; obs_init_module must
  be called on the module pointer in order to fully initialize the
  module.  This is done so a module can be disabled by the front-end if
  the it so chooses.

New API:
- void obs_add_module_path(const char *bin, const char *data);

  These functions allow you to specify new module search paths to add,
  and allow you to search through them, or optionally just load all
  modules from them.  If the string %module% is included, it will
  replace it with the module's name when that string is used as a
  lookup.  Data paths are now directly added to the module's internal
  storage structure, and when obs_find_module_file is used, it will look
  up the pointer to the obs_module structure and get its data directory
  that way.

  Example:
  obs_add_module_path("/opt/obs/my-modules/%module%/bin",
                      "/opt/obs/my-modules/%module%/data");

  This would cause it to additionally look for the binary of a
  hypthetical module named "foo" at /opt/obs/my-modules/foo/bin/foo.so
  (or libfoo.so), and then look for the data in
  /opt/obs/my-modules/foo/data.

  This gives the front-end more flexibility for handling third-party
  plugin modules, or handling all plugin modules in a custom way.

- void obs_find_modules(obs_find_module_callback_t callback, void
                        *param);

  This searches the existing paths for modules and calls the callback
  function when any are found.  Useful for plugin management and custom
  handling of the paths by the front-end if desired.

- void obs_load_all_modules(void);

  Search through the paths and both loads and initializes all modules
  automatically without custom handling.

- void obs_enum_modules(obs_enum_module_callback_t callback,
                        void *param);

  Enumerates currently opened modules.

libobs/obs-windows.c

@@ -27,57 +27,32 @@ const char *get_module_extension(void)
 	return ".dll";
 }
 
-static inline bool check_path(const char* data, const char *path,
-		struct dstr * output)
-{
-	dstr_copy(output, path);
-	dstr_cat(output, data);
-
-	blog(LOG_DEBUG, "Attempting path: %s\n", output->array);
-
-	return os_file_exists(output->array);
-}
-
-static inline bool check_lib_path(const char* data, const char *path,
-		struct dstr *output)
-{
-	bool result = false;
-	struct dstr tmp;
-
-	dstr_init_copy(&tmp, data);
-	dstr_cat(&tmp, ".dll");
-	result = check_path(tmp.array, path, output);
-
-	dstr_free(&tmp);
-
-	return result;
-}
-
-/* on windows, plugin files are located in [base directory]/plugins/[bit] */
-char *find_plugin(const char *plugin)
-{
-	struct dstr path;
-	dstr_init(&path);
-
 #ifdef _WIN64
-	if (check_lib_path(plugin, "obs-plugins/64bit/", &path))
+#define BIT_STRING "64bit"
 #else
-	if (check_lib_path(plugin, "obs-plugins/32bit/", &path))
+#define BIT_STRING "32bit"
 #endif
-		return path.array;
 
-#ifdef _WIN64
-	if (check_lib_path(plugin, "../../obs-plugins/64bit/", &path))
-#else
-	if (check_lib_path(plugin, "../../obs-plugins/32bit/", &path))
-#endif
-		return path.array;
+static const char *module_bin[] = {
+	"obs-plugins/" BIT_STRING,
+	"../../obs-plugins/" BIT_STRING,
+};
 
-	dstr_free(&path);
-	return NULL;
+static const char *module_data[] = {
+	"data/%module%",
+	"../../data/obs-plugins/%module%"
+};
+
+static const int module_patterns_size =
+	sizeof(module_bin)/sizeof(module_bin[0]);
+
+void add_default_module_paths(void)
+{
+	for (int i = 0; i < module_patterns_size; i++)
+		obs_add_module_path(module_bin[i], module_data[i]);
 }
 
-/* on windows, points to [base directory]/libobs */
+/* on windows, points to [base directory]/data/libobs */
 char *find_libobs_data_file(const char *file)
 {
 	struct dstr path;
@@ -93,22 +68,6 @@ char *find_libobs_data_file(const char *file)
 	return NULL;
 }
 
-/* on windows, data files should always be in [base directory]/data */
-char *obs_find_plugin_file(const char *file)
-{
-	struct dstr path;
-	dstr_init(&path);
-
-	if (check_path(file, "data/obs-plugins/", &path))
-		return path.array;
-
-	if (check_path(file, "../../data/obs-plugins/", &path))
-		return path.array;
-
-	dstr_free(&path);
-	return NULL;
-}
-
 static void log_processor_info(void)
 {
 	HKEY    key;