Cleanup: Refactor Helpers / ExtensionMethods dirs

Helper classes & extension methods are now
cleanly divided between these two directories.
LESS: Fix compilation corner cases

Don't crash if no project is open,
or if source maps are disabled.
Merge pull request #296 from SLaks/helper-cleanup

Cleanup Helpers & LESS compilation
Merge pull request #297 from am11/master

Analysis: various warnings fixed.
Analysis: (CA1012) Abstract type has constructor.