Clean up the MSVC project files

Remove nonexistent include directories, remove unused include directories (encoder directories included in the decoder). Unify include directores across configurations (debug vs release, win32 vs x64) (this simplifies keeping them in sync if updating them via the GUI, when all 4 can be updated at once). Remove unnecessary extra empty sections for file specific options (we should not set compiler options specifically per file unless absolutely necessary) and remove manually set SuppressStartupBanner options (that were set to the default value).

All in all, this shortens the vcproj files by 1426 lines.