ReflectionModelLoader #1723: quote class parts
Test for #1723: ModelResolutionException when getting metamodel of object called ‘package’
Renamed module/package descriptors #1723: to $module_ and $package_ to avoid clashes

Consequently, unescaped toplevels named package and module.
ReflectionModelLoader #1723: fix how we quote names
Updated tests for #1723: module/pacakge descriptor class rename