CONTRIBUTING.md: fix path to run_astyle.bat
solution files: remove RARFileSource from Lite builds.

We don't link it so there is no need to build RARFileSource.
Also fix the platform for Lite builds even if it's unused.
Build.bat: Add loop for signing. In case of failure we will know exactly which file is the problem.

Based on XhmikosR's ideas.
Updated Slovak translation.

Closes pull request #73.
build.bat: Fix resources files signing after e515bd9998817c0286d676b731f29e1ccc69a11e