Make Timezones pytz compatible

[ericsandine]

It seems like Timezone Name should be a pytz compatible name so it can be used as a valid timezone in Python. I'm not sure if that's what you intended or not but I figured I would open this PR in case other people are looking for it. Feel free to close if that wasn't the intention here.

This is the before:

In [49]: for key, value in facebook_timezones.facebookTimezoneIdToTimezoneName.iteritems():
    ...:     try:
    ...:         pytz.timezone(value)
    ...:     except:
    ...:         print 'Unknown %s' % (value)
    ...:
Unknown Unknown
Unknown America/Argentina_San_Luis
Unknown America/Argentina_Buenos_Aires
Unknown America/Argentina_Salta
Unknown America/Blanc_Sablon
Unknown America/Port_Of_Spain
Unknown Num/Timezones

Might be a better idea to swap this for something like facebookTimezoneIdToPytzTimezoneName?