Add accept/reject features
Merge branch 'features' of https://github.com/albertcui/gawk into features

Conflicts:
	parser.mly
	scanner.mll
Merge branch 'features' of https://github.com/albertcui/gawk into features

Conflicts:
	parser.mly
Merge branch 'features' of https://github.com/albertcui/gawk into features