Reimplement monitor capture

- Implement windows monitor capture (code is so much cleaner than in
   OBS1).  Will implement duplication capture later

 - Add GDI texture support to d3d11 graphics library

 - Fix precision issue with sleep timing, you have to call
   timeBeginPeriod otherwise windows sleep will be totally erratic.

plugins/win-capture/plugin-main.c

@@ -0,0 +1,13 @@
+#include <obs-module.h>
+
+OBS_DECLARE_MODULE()
+
+extern struct obs_source_info monitor_capture_info;
+
+bool obs_module_load(uint32_t libobs_ver)
+{
+	obs_register_source(&monitor_capture_info);
+
+	UNUSED_PARAMETER(libobs_ver);
+	return true;
+}