code cleanup

- use _: Block instead of quasiquote
- remove obsolete commented out lines
- use ListMap instead of Map in Object
- rename _super to static in selects
- remove obsolete call to extendHeap in FunctionValue.apply()
- use Nil to match an empty list
- move initialized field to ModuleValue
- rename ObjectCons* to ObjectCtor*
- refactor extraction of templates from ImplDefs
- rename params to argss in ObjectCons.apply()
- rename selectOverride to selectMethod
- remove excess code in static method selection
- fix typo in ObjectValue.select() env->env1
- fix typo in error message
lazy initialization of module body
fix overloading in selectMethod

- find overloaded method by its type signature
- add overloading test