Add __repr__ method to SimpleStatement and PreparedStatement. This should help
with debugging.
Throw InvalidParameterTypeError  exception if user trys to bind
PreparedStatement with an argument of an invalid type.
Modify InvalidParamaterTypeError to inherit from TypeError.
Also include consistency level in the __repr__.
Merge pull request #25 from Kami/throw_better_exception_when_binding_preparedstatement_with_invalid_type

Throw a better exception which user binds PreparedStatement with an argument of an invalid type
missing connection check before returning it

checking if the connection still exists solved lots of random AttributeError exceptions 'NoneType' object has no attribute 'lock'

looking few lines up seems like this check is necessary
Merge pull request #31 from tbarbugli/patch-1

missing connection check before returning it
Install unittest2 as a test dependencies when running tests under Python 2.6.

Currently tests would blow up if they were run under 2.6 because they were
relying on unittest functionality which is only available in Pyton >= 2.7.

Conflicts:

	tox.ini
Use set instead of set literal, because set literal is only available in Python
> 2.7.
Merge branch 'master' of https://github.com/datastax/python-driver
make blist a dependencyto get sortedset; use util.py OrderedDict it < 2.7