Cqlengine

* removed default values from all column types
* explicit primary key is required (automatic id removed)
* added validation on keyname types on .create()
* changed table_name to __table_name__, read_repair_chance to __read_repair_chance__, keyspace to __keyspace__
* modified table name auto generator to ignore module name
* changed internal implementation of model value get/set
* added TimeUUID.from_datetime(), used for generating UUID1's for a specific
time

* added abstract base class models

* comprehesive rewrite of connection management (thanks rustyrazorblade)

* added support for Token function (thanks mrk-its)
* added support for compound partition key (thanks mrk-its)s
* added support for defining clustering key ordering (thanks mrk-its)
* added values_list to Query class, bypassing object creation if desired (thanks mrk-its)
* fixed bug with Model.objects caching values (thanks mrk-its)
* fixed Cassandra 1.2.5 compatibility bug
* updated model exception inheritance

* adding support for datetimes with tzinfo (thanks gdoermann)
* fixing bug in saving map updates (thanks pandu-rao)

* expanding internal save function to use update where appropriate
* adding set, list, and map collection types
* adding support for allow filtering flag
* updating management functions to work with cassandra 1.2
* fixed a bug querying datetimes
* modifying datetime serialization to preserve millisecond accuracy
* adding cql function call generators MaxTimeUUID and MinTimeUUID