implement class_alias()
Fix is_a()/is_subclass_of()
Allow namespaced class names when specifying a callback
Don't autoload invalid names in is_a()/is_subclass_of()
Update conftest
fix order of operations in get_callback()
Fix interaction of class_alias() with exceptions and typehints
Don't autoload when typehinting or catching an exception
Merge pull request #68 from rlamy/class-alias

implement class_alias()