Added $class parameter to Connection::query() for consistency.
Added docs for custom queries.
Moved low database logic from Query to Connection

Updated the Query object to use methods from Connection which already
have most required logic.

Added Connection::preparedExecute() which was required.
Fixed bug with pgsql introduced in previous commit.
Added Connection::getDriver()
Merge branch 'develop' of https://github.com/ihabunek/phormium into develop

Conflicts:
	src/Phormium/Connection.php
test case for making sure select + update works