Video replay tool

A tool to replay a video of a flight in sync with the replay of the log. The documentation is available here : 

https://wiki.paparazziuav.org/wiki/Video_replay

To test it, you need to delete your conf/control_panel.xml, in order for the make to regenerate it with the new tool. A make clean doesn't do it.

Should use different address on OSX, e.g. like it's done in https://github.com/paparazzi/paparazzi/blob/master/sw/simulator/nps/nps_ivy_common.c#L64