fix build
rendermanager: add SceneGraph and abstracted render functions for gl/gles
rendermanager: remove GUITexture inheritance and send batched regions to the scene graph
rendermanager: nuke old gl/gles texture renderers
rendermanager: remove inheritance from CBaseTexture.

Add a "RenderObject" member that represents an abstract gpu texture handle.
It is defined as a void*, and should be cast by each implementation to whatever
it represents. For example, gl/gles both define it as a GLuint (unsigned int).

It should NOT have a hard-coded build-time definition.

Also, add some helper functions for getting at the texture easier.
rendermanager: fix renamed classes
rendermanager: remove old texture uploader
rendermanager: add A8L8 texture format

This represents GL_LUMINANCE_ALPHA in GL-speak. Suitable for our fonts.
rendermanager: abstract font rendering

1. Take advantage of CGUITextureBase to handle our texture upload.
   GUITextureBase has its own backing store, which is deleted after upload
   since it may be undefined. Because of this, we keep a cached copy of the
   texture in GUIFontTTF and submit the updates to the texture when needed.

2. Batch up the draws and send them to the scene graph.

3. Switch to a 2-byte texture. First byte is solid, second is the alpha value.
   When rendered, this will be treated by GL as RGBA (255,255,255,a). We use
   a uniform color throughout rather than per-vertex as before. Combining these
   things, we can use our texture shaders with zero state changes.

   Note: The texture is copied with the correct stride for any desired format,
   so if other renderers would prefer rgb/rgba/bgra/etc, they can easily be
   substituted per-renderer.
rendermanager: remove old font upload/render classes
rendermanager: remove old font-texture cleanup functions from TextureManager
rendermanager: add gles uniform for diffuse color

We no longer have any need for per-vertex colors in the gui, so use a uniform
as a significant performance gain
rendermanager: move most of the render logic out of GUIWindowManager

1.  Don't clear. GL needs to do this last thing before starting to render, else
    we can block needlessly while waiting for a buffer. Let the renderer handle
    it.

2.  Don't worry about dirty regions or scissoring. Do a RenderPass, then give
    the results to the renderer. It will best how to deal with the results.

3.  Draw the dirty region visualizers as part of the scene graph, just like any
    other GUI element.
rendermanager: remove deleted files from build
rendermanager: CBaseTexture fixups
rendermanager: use scene-graph DrawQuad
rendermanager: update shaders to use uniform color

Also change multiply order on multi+blend to save an op
rendermanager: abstract picture slideshow
rendermanager: hack. Draw the current scene before rendering video

This is a hack to avoid having to rewrite all of the current video renderers.
rendermanager: use the same video-render hack for render controls