Add lookahead to grammar context
Add lookahead to grammar context

Allow users to get a lookahead when parsing a grammar. This can be used
to resolve some grammars where the 0 lookahead is not enough.

haka-security/haka,haka-security/haka,LubyRuffy/haka,Wingless-Archangel/haka,Wingless-Archangel/haka,lcheylus/haka,nabilbendafi/haka,nabilbendafi/haka,lcheylus/haka,lcheylus/haka,LubyRuffy/haka,nabilbendafi/haka,haka-security/haka