Fixed links to mysqlclient in database notes.

- `MySQLdb`_ is a native driver that has been developed and supported for over

  a decade by Andy Dustman.

- `mysqlclient` is a fork of ``MySQLdb`` which notably supports Python 3 and

- `mysqlclient`_ is a fork of ``MySQLdb`` which notably supports Python 3 and

  can be used as a drop-in replacement for MySQLdb. At the time of this writing,

  this is **the recommended choice** for using MySQL with Django.

- `MySQL Connector/Python`_ is a pure Python driver from Oracle that does not

mysqlclient

~~~~~~~~~~~

Django requires mysqlclient 1.3.3 or later. Note that Python 3.2 is not

Django requires `mysqlclient`_ 1.3.3 or later. Note that Python 3.2 is not

supported. Except for the Python 3.3+ support, mysqlclient should mostly behave

the same as MySQLDB.