Minor bugfixes

Hi,

I've made some small changes to LinOTP, and I thought you might find them useful:

* Fix typos ('seletected' & 'dynanmic') in manage.js and selfservice.py
* Change a log.error to log.debug in getSupportInfo (currently it uses log.error to say it's finished)
* Improve language detection in base.py - some browsers send 'en-gb' or 'en-GB' instead of 'en'

Thanks,

richarddlmay