no longer passing Parser/Lexer masquerading as superClass option.
Merge pull request #610 from parrt/superClass-codegen-change

no longer passing Parser/Lexer masquerading as superClass option.
Merge branch 'master' of https://github.com/antlr/antlr4 into Preliminary-enhancements-for-Python-target

Terence's implementation
cleanup after merge