Merge pull request #70 from haizaar/master

Python 3 compatability
Update version numbers and changelog.
Fix in Pool.register_hstore()
Merge pull request #71 from mpyatishev/patch-1

Fix in Pool.register_hstore()

Thanks!
Tornado 4.0 compatablity

Backported old Task class for Tornado 4.0 compatablity. This
will hold until we migrate to new interface