#24 Support generics with multiple type parameters as ReturnType

[Anonymous]

JBurn's grammar parser doesn't allow generic ReturnType with more than one parameterized types.

For example:
...
ReturnType Pair<string, integer="">;
...</string,>

Got error message:
[java] line 41:32: expecting RANGLE, found ','
[java] line 41:34: expecting SEMI, found 'InstructionList'
[java] Error: JBurg terminating due to parse errors.