Remove MSVC solution user state files that shouldn't be version controlled
Remove the 2010 and 2012 MSVC project files from WelsVP as well

The corresponding files for the decoder and encoder were
removed in ccca04453a3. The 2008 version can be imported into
MSVC 2010 and 2012 just fine, reducing the amount of project files
to keep in sync.
Remove the unused solution and project files for WelsVideoProcessor

These are for building source files that aren't present in the
project any longer.
Remove the MSVC solution for WelsVP

This isn't necessary, it can be built via the encoder solution.
Merge pull request #202 from mstorsjo/remove-extra-msvc-projects

Remove unused/superfluous MSVC project files