added GNUMakefile.  Further testing needed.

added enter to events.c to act for selecting.
GNUMakefile works! ...and now i remembered i didn't change the CC to just gcc...freebsd has the ports of gcc including their version number (so gcc49 is what i was using to test the GNUMakefile).  next commit will change it to just gcc...

learned something cool about returning strings, game_gettitle shows it off.  works like a charm.
fixed GNUMakefile to use gcc instead of gcc49
Merge branch 'master' of https://github.com/damikin/snake