Manually merged in yaronr's pull request  to make the size of the image much smaller

Also resolved a merge conflict - we're back to Java 8u20
Update readme: specifying listen_address
Add support for changing 'listen_address' in cassandra.yaml by providing the -e LISTEN_ADDRESS env var
Link option added, example of how to run a script from CQLSH
Merge pull request #16 from ipedrazas/master

Link option added, example of how to run a script from CQLSH
Merge remote-tracking branch 'upstream/master'

Conflicts:
	cassandra/Dockerfile