Basic (working) counter column.  You can add and subtract values.  You must use CounterModel when using a CounterColumn.
Merge branch 'master' of https://github.com/bdeggleston/cqlengine
Custom TTL and timestamp information can be passed in on save.
Merge branch 'master' of github.com:bdeggleston/cqlengine
Merge branch 'master' into ttl
Merge remote-tracking branch 'cqlengine/master'

Conflicts:
	cqlengine/columns.py
	cqlengine/connection.py
	cqlengine/models.py
	cqlengine/query.py
Reverted the changes I made as everything I had done is in the code base now.
Allow for a default TTL.
Changed DEFAULT_TTL to __default_ttl__ and added tests.
Added docs around __default_ttl__
Merge pull request #242 from gdoermann/master

Add default TTLs to queries and models.