Fix more compilation errors

Apparently API stability is for wussies.

the RTSPClientSession class was changed to no longer have the stuff that
we need for tally light operation; instead, the relevant things have
moved to a new class "RTSPClientConnection". The difference is that a
Session may persist over several Connections.

Update our code to match.

Compiles, but does not link yet; this is likely due to a
multiarch-related change in packaging for libLiveMedia.
Check for Boost.System and link with it

Recent versions of Boost require users of Boost.Thread also to link with
Boost.System, so let's do that.
Build-Depend on libboost-system-dev
Explicitly include libavutil/mem.h

av_free is no longer exposed via avcodec.h and libavutil/mem.h needs to be
included.
Fix manual fade behaviour

Previously, as detected during debconf, enabling the "manual fade"
function even once during a dvswitch session, would from then on
automatically enable it again once a secondary feed was chosen, even if
the manual fade function was disabled in the interface.

This is wrong, confusing for the dvswitch operator, and fairly annoying
for people watching the streams, so fix that behaviour.
0010-happy-alsa.diff committed.
This helps building dvswitch manually. Not sure why the buildservice does not need this.
Added recording (not really usefull due to frequent dropouts)
Usage improved.
Added ping test before connecting to bambuser.