movistar_u7d.py & vod.py: catchup load times as lower as they can be,

to go lower I need to get hired by Movistar and tune it myself. This
meant a huge refactoring in vod, now fully asynchromous and runnable
both from within movistar_u7d as well as a separate process, so
recordings continue to be independent from movistar_u7d once launched.

Signed-off-by: Javier Marcet <javier@marcet.info>