* Prevents circular linking of docs
- also added test case to check if code to prevent circular linking of
doctypes works
* created a CircularLinkingError class
- this can be used later if circular linking error needs to be thrown
elsewhere
* added PyMYSQL instead mysqlclient-python
* added pymysql import
* fixed db module import
* foxed self._conn wrapper
* updated cursor migration
* removed existent converters
* some more fixes towards API port
* modified travis
* updated doctype and revereted yml
* modified travis
* refreshed logging
* raw fix
* moved from hard coded constants to declarable instances
* moved from hard coded constants to declarable instances
* refactoring and logging
* moved to global import declaration
* fixed codacy
* unfixed codacy
* minor fix
* binary_type has a single
* deprecated alternative
* merged with latest
* fixed merge conflicts
* using deprecated alternative
* raw fix
* stupid fix
* using StringTypes instead
* brutal hack
* log
* tundebazy to the rescue
* fixed content_hash error
* frappe/database.py
* frappe/database.py
* updated database.py
* updated requirements
* updated requirements
* fixed codacy
* fixed codacy
* moved from DatabaseOperationalError to pymysql.InternalError
* moved from DatabaseOperationalError to pymysql.InternalError
* fixed codacy
* empty commit
* fixed codacy
* fixed codacy
* adds new exception to be raised when any improper database configuration is detected
* changes behavior of `check_if_ready_for_barracuda` to raise ImproperDBConfigurationError instead of sys.exit`
* refactors `drop_site` to use a new exactly identical `_drop_site` function.
The reason for this is because the original `drop_site` function is decorated
and cannot be undecorated without nasty hacks. Breaking the function this way
allows me to make use of the `drop-site` logic easily.
* catches the ImproperDBConfigurationError raised from `check_if_ready_for_barracuda` function to drop all the artifacts of the failed new `Site`
