Subtitles: Add option to render subtitles at source video resolution.

Fixes #60
VideoRenderers: Set the video size through a setter.

Don't set the aspect ratio to the video size anymore when it is not known, this case is already handled by GetVideoSize().
VMR7: Use GetVideoSize() instead of correcting the aspect ratio explicitly.
VideoRenderers: Fix GetNativeVideoSize returning an invalid aspect ratio.

The multiplication was invalid, the documentation specifies that only the aspect ratio needs to be returned.
Update Release.txt
MainFrame: properly remember last d3dfs state
MainFrame: destroy d3dfs window if vr is missing
MainFrame: make bExtOnTop visible to class
Don't drop out of fullscreen when loosing focus

Instead, unset the "on top" flag.
AboutDlg: recognise vs2013 update 2
Don't use GetSectionKey() in HasProfileEntry()

It creates section key if the section is missing.
Don't create empty section in settings migrator

"DVB configuration" was being created.