Added the small necessary changes to the VS2012 projects
Integrate VS2012 build into build_vsfilter.sh to avoid code duplication

Fix "-projects" switch not being parsed.
Change "-projects" to "-proj" in usage text and add VS2012 usage.
Remove redundant imports from project files

This also fixes warnings in debug builds
Add .gitignore adapted from MPC-HC

Also remove some *.user files from the repo