Vertica-python

* Removed psycopg2 dependency (i.e. removed `pip install 'vertica-python[namedparams]'`) (276)
* Fixed 272: Make THROW_ERROR function throws an error (277)
* Improved cursor close logic (274)

* Fixed 147: Added SHA512 authentication support (266)
* Fixed 180: Added password expiration logic (268)
* Added authentication tests (270)

* New Feature: server-side prepared statements
* Support UDtypes (GEOMETRY & GEOGRAPHY)
* Update README
* Add more debug logging
* Fix DBAPI type object for python 3

Fix 251: Write notice messages to log

* Upgrade supported Vertica protocol to 3.4
* Add session_label connection setting (241)
* Fix 185 (242)
* Add more info to cursor.description (244)
* Add LostConnectivityFailure error (245)

* Added Vertica Connection Load balancing and Failover features
* Added logging feature
* Improved test framework
* Travis CI Setup
* Several fixes: 209 175 233 179 213 181