Fix GetAtomName

- We were not catching the atoms.
- We were leaking the Client.pending_atoms object.
- Fix test so it does what it was supposed to do.
Merge pull request #36 from santigimeno/fix_get_atom_name

Fix GetAtomName
add EnterWindow event, and give events names
Merge pull request #37 from dominictarr/master

add EnterWindow event, and give events names
0.3.1