Update Makefile to call run_tests.py $(EXECUTABLE)
use the CC envvar if it is set
Avoid a NULL pointer dereference (that clang sees)
add the gcode files that somehow got missed
use CXX instead of CC in Makefile
Simple fix for the unittests for the moment
Test against compressed gcode
Ignore gcode files since tests use compressed versions
Merge pull request #26 from grimmy/master

Update Makefile to call run_tests.py $(EXECUTABLE)