Pass options through connect to MySQLdb.connect

Using flaskext.mysql it is impossible to pass extra keyword arguments to 
MySQLdb.connect.

For instance, I want to change the cursorclass to be MySQLdb.cursors.DictCursor.

This change passes through any keyword arguments supplied to connect to MySQLdb.connect.

I also have it where a keyword arguments overrides any of the self.app.config settings.