webdb: Reordered drivers/base.py functions
webdb.drivers.base: rewrote add_column, added _add_column
webdb: Created __db_api_init__ shortcut
webdb: Adapted mysql to new __db_api_init__
webdb: Removed connection parameter storage from drivers
webdb.drivers.mysql: Moved engines list into class namespace
webdb: Reformatted Column docstring to reStructuredText
webdb driver testing: Adding test connection to driver docstrings
webdb.drivers.base: Removed obsolete driver_base docstring
webdb: Removed explicit doctesting of drivers
webdb.drivers.base: Added docstrings to driver_base functions