Massive refactoring of xenia::ui and GL swap behavior.

This seems to dramatically improve most games (especially with
--vsync=false), though it may cause swap issues with others.
New code should be easier to port, and enables elemental-forms to be
drawn for any emulator UI.

src/xenia/profiling.h

@@ -148,11 +148,8 @@ class ProfilerDisplay {
 
 class Profiler {
  public:
-#if XE_OPTION_PROFILING
-  static bool is_enabled() { return true; }
-#else
-  static bool is_enabled() { return false; }
-#endif  // XE_OPTION_PROFILING
+  static bool is_enabled();
+  static bool is_visible();
 
   // Initializes the profiler. Call at startup.
   static void Initialize();