add BigInt column
Allow use of timezone aware datetimes in {Max,Min}TimeUUID

Convert the given timezone aware datetimes to UTC in a similar manner
as the DateTime column type does instead of resulting in an error.
Merge branch 'master' of github.com:Lifto/cqlengine into pull-116
Merge branch 'tzaware-functions' of github.com:dokai/cqlengine into pull-118
Merge remote-tracking branch 'origin/master' into ttl