Prevents losing sync when remuxing streams with different
start times. The smallest start time is selected as
the base time and all timestamps are subtracted
from it to get the actual time to be used when
muxing and building indexes
Fixes#586848
asfmux was messing up with the GstCollectData list of its
GstCollectPads when sorting the list inplace. This patch makes
it copy the list before sorting it, leaving the GstCollectPads
list as is. Fixes#591610
Adds the brand new asfmux plugin, containing 3 elements:
asfmux, rtpasfpay and asfparse. This plugin was developed
as a GSoC 2009 project, with David Schleef as the mentor and
Thiago Santos as the student.
