Feature/better tz

This PR makes OW set a real time zone for it's users, which would fix #212 and #210. It includes a python script to generate a dictionary mapping olson to posix timezones. I have also included the dictionary, pre-generated so that it is available to set the timezone the moment the person turns on their router.  The gen_tz_dictionary should probably be put on a cron job. It shouldn't have to run very often though. Once per month is probably sufficient since timezones don't change that often.
Could you also fix this to use common.get_etc at runtime (i.e. inside the function)? That would fix running lighttpd locally, since it needs to override the path to /etc/.