Create syntactically valid method stubs for methods with unsafe names
Improve method set up logic for oddly-named methods

WithMethods#attach_and_define_method:
- Remove old method only if it exists
- Remove method by its safe name
- Return safe name after creation
ClassBase#setup_method:
- Call created method by the returned safe name
Add override for GLib::IConv.open
Prepare version 0.7.1 for release