RenderManager refactoring

Here are some render manager and dvdplayervideo refactoring that had queued up in my 3d branch. Thought i'd split them out.

They will cause conflicts with https://github.com/xbmc/xbmc/pull/2309 but I think they do create a better base for that to stand on. The removal of frame waits in application are directly stolen from the buffering pull, but implemented inline with the current event model in the render manager.

I know this will create a messy merge for @FernetMenta, I may have some time to do that merge he following days thou.