Added in support for multiple bases
Added in support for multiple bases

Removed explicit support bases and added in a more general base support.
This pushes the responsibility of error messages to the visitor rather
than the lexer which would result in a more user friendly error message

antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4,antlr/grammars-v4