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/ui/graphics_context.cc

@@ -0,0 +1,21 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2015 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/ui/graphics_context.h"
+
+namespace xe {
+namespace ui {
+
+GraphicsContext::GraphicsContext(Window* target_window)
+    : target_window_(target_window) {}
+
+GraphicsContext::~GraphicsContext() = default;
+
+}  // namespace ui
+}  // namespace xe