UPDATED:
- CKAN Dockerfile
	- improved caching of common requirements with the Datapusher
	- Added $CKAN_INI env variable
	- downgraded to pip 1.4.1 because 1.5 has a bug with HTTPS proxies https://github.com/pypa/pip/issues/1805
	- fixed incorrect default port exposed
- Fig Dockerfile to 1.0.1
- fig.yml
	- mount the custom_options.ini as a volume
	- use relative path by default
- Documentation
ADDED:
- Datapusher Dockerfile based on fusion baseimage.