Added GPLv2+ as license for libgrammatic
Fixed assertion in first The implementation assumed there would be no rules starting with terminals since they were eliminated at the first chance. However, rules starting with a non-terminal which produced the empty string followed by a terminal were added to the set of rules. git-archimport-id: cascardo@tlscascardo--private/libgrammatic--nogobject-lr1--0.1--patch-10