Add cppcheck capability ... can now be chosen with 'scons cppcheck=1'

Creates a file called cppcheck_report.txt in the top level directory ..
fails with error message if cppcheck is not installed or if not in PATH.

Fixes #32
Bugfixes for cppcheck implmentation
Final debugging changes ... now works on MacOSX, Linux, and fails
properly if cppcheck is not installed.
Add instructions for cppcheck
Seems I have to commit these in order to rebase ...
Merge branch 'develop' of github.com:brash99/hcana into develop