Fix Daily Show and Colbert Report

Fix the Daily Show and Colbert Report, which broke after the new web site layout. Full episodes and clips are working.

* Site now works with a JSON object that holds all video data. This is parsed using simplejson. 
* The air date is stored in unix time in the JSON object. It is the original air date & time of the episode (i.e. 11pm or 11:30pm). This means that for countries east of the US, the air date would be displayed as one day later (e.g. date+1 @4am for west Europe). A new function is added to _common to convert between timezones. This does not depend on an external library like pytz, so it it not really that good. It does not take into account any DST effects)