New expression parser operator system
Merge branch 'develop' of https://github.com/antonijn/acc into develop

Conflicts:
	src/parsing/expr.c
-D_GNU_SOURCES is awful and completely unnecessary
Merge branch 'develop' of https://github.com/antonijn/acc into develop
Fixed the fact that I broke EVERYTHING
Colorised error output :3
Merge branch 'develop' into codegen