use a predefined pool for keyspace ops
Obscure bug involving 'fake' keyspaces being visible

* A pool is spun up for each keyspace
* If a keyspace doesn't exist, but is 'used' (e.g. describe_..)
        then the pool is spun up
* This causes subsequent requests (after the pool is created)
        to fail, since the pool is dangling
* The solution is to use a predefined pool for all keyspace ops
        and to start this pool up if it doesn't exist
Add lager and goldrush as dependencies of erlang_cassandra.
Merge branch 'dieswaytoofast_CloudI-develop' into develop

Conflicts:
	src/ChangeLog