Initial implementation with file and zookeeper.

* Individual implementations are in pok/impl.
* Merging logic in pok.config.merge_configs.
* The usual setup, scripts, version.

	modified:   README.md
	new file:   pok/__init__.py
	new file:   pok/config.py
	new file:   pok/impl/__init__.py
	new file:   pok/impl/file.py
	new file:   pok/impl/zk.py
	new file:   pok/version.py
	new file:   requirements.txt
	new file:   scripts/rm_all_pyc.sh
	new file:   scripts/set_permissions.sh
	new file:   setup.py