Integration pure python mysql driver

MySQLdb has issues on various platforms - especially older platforms like RHEL4 where utf8 support is entirely broken. On newer platforms MySQLdb spits out warnings due to deprecated modules. A pure-python driver like pymysql (http://code.google.com/p/pymysql/) or myconnpy (https://launchpad.net/myconnpy) can avoid most (if not all) of these headaches and potentially can reduce the dependencies when deploying holland.