Added GPLv3 license.
Added license headers.
Merge branch 'master' of https://github.com/trira/BFInterpreter

Conflicts:
	BFInterpreter.c
	BFInterpreter.h
	main.c

Git told me something was wrong.
Merge branch 'master' of https://github.com/trira/BFInterpreter

I really don't know.