Revert "ecore: Create Promises"

Revert "ecore: Create Promises"

Reverting this at Felipe's request following my email. There are many
things I strongly object to in this commit. I've touched the surface of
those on the ML (which doesn't work at the moment), though we need to
better discuss it.

The gist:
1. dlsym is a really bad hack that is not even needed.
2. I don't see why eo should even be aware of promises. It's not aware
of list, hash and etc.
3. The eolian changes were done wrong.

This should have been discussed and consulted before done, even if only
because of the amount of hacks it includes and the cross-domain (ecore,
eo and eolian) nature of it.

This reverts commit f9ba80ab33e0b94dad7ec103e6d261a644f7835f.