Add the ability to choose the scale factor for the auto-fit zoom.

The factor is relative to the screen size.
fixed select subtitles
(if the subtitles were disabled earlier, had to turn twice)
MainFrm: Check if pDVDI is initialized in SetupDVDChapters()
add VS2012 projects (WIP)
remove _ProjectFileVersion
point ProjectReference entries to the new _vs2012 project files
Move platform toolset property to platform.props. Patch inspired by LAVFilters.