Remove unused CGAbstractStaticMethod class.
Remove some dead code from CGAbstractMethod._decorators.
Stop pointlessly indenting GetProtoObject.
Cleanup the code in PrototypeList().
Cleanup and simplify CGImports.
Reorder GetProtoObject.
Remove some C++-related code in BindingGen.py.
Remove a pointless argument to generate_file in GlobalGen.py.
auto merge of #1883 : Ms2ger/servo/cleanup-codegen, r=jdm