eo: here comes reflection API
this adds support in eo to generate a reflection API. To get the actaul
reflection to the klass, the API efl_class_reflection_table_set needs to
be called, the table in the end can be generated by eolian. Reflection
API is inherited by the extended class. This means, if you have two
reflection tables, first, the most upperst is called, then the next
lower one is called.
For now this API accepts NULL setter or getter, and will ignore them
silently when they are called.
Differential Revision: https://phab.enlightenment.org/D7879