contrib/mpc-hc.cppcheck: Add library and suppressions settings.

Requires cppcheck https://github.com/danmar/cppcheck/commit/24a9da37718a79fa4cabdad59bf71426722e22c7 or newer.
Remove duplicate expression.
Bump copyright year to 2014.
Compilation.txt: update msysGit version.
build.bat: clean up 7za path.
build.bat: Simplify checks
build.bat: Simplify some code
coverity.bat: Add 7-Zip detection logic