libav: fixed minor memory leak when errors accurs.
libav: drop h264 packets when bitstream filter fails
Fix #1643 - dvb: alter the way we handle dvb tuning

This ensures that demux filters are not installed until after tuning
is locked. This should resolve most stale data issues.
support: remove confusing (and uncessary) default values.
gtimer: increased resolution of the gtimer system.

This is needed to resolve a dvb tuner deadlock issued caused by my
re-jigging of the tuning setup code.
Fix #1666 - dvb: rework the adapter tuning to stop possible deadlock
Fix #1674 - remove spurious (info) log message before daemon().
support: some updates to build system
gtimer: fix live lock problem caused by wrong clock usage
dvb: demux setup code went missing!
constify strtab
Deal with POSTs that are empty
Implement updating of properties from webui
Add code for updating webui when title / descriptors are changed in tvh
idnode: Rename descriptors -> parameters
Add support renaming of DVB networks
dvb: fix problem stopping DVB-S muxes being added on DVB v3 systems
Fix #1679 - correct mistake in previous changes to stop constant IO

TSID was not being properly updated, which could result in missing
services.
capmt: fix capmt for multi-frontend adapters
debug: added new tvhtrace logging routine

Note: this can be compile switch disabled (./configure --disable-trace)

Note: to enable subsystem output use --trace X,Y,Z etc... (--trace all
will enable the lot).

Note: the only way to know what subsystems are valie is to read the code!

Note: --trace implies -d