src/dvb: implement EN50494 SCR tuning
webui: add EN50494 config bits
dvb: shut down en50494 SCR on power down event
src/dvb/diseqc: add method for EN50494 SCR tuning

EN50494 ("Unicable") basically sends special DiSEqC commands to the
LNB / switch matrix to select a channel and frequency, later the
frontend is tuned to a fixed freq.
This blends in pretty easily with diseqc_setup, so just add a similar
function named en50494_setup.
Merge branch 'master' of github.com:tvheadend/tvheadend

Conflicts:
	src/dvb/diseqc.c
	src/dvb/diseqc.h
	src/dvb/dvb.h
	src/dvb/dvb_adapter.c
	src/dvb/dvb_fe.c
	src/webui/extjs_dvb.c
	src/webui/static/app/dvb.js
Merge branch 'master' of github.com:tvheadend/tvheadend
Merge branch 'master' of github.com:tvheadend/tvheadend
support: updated some random helper scripts
mpegts: ensure that PCR (and PMT) are properly opened by service and recorded.

Fixes #1884.
main: provide option to make daemon dumpable
mepgts: correct invalid interpretation of service type in VCT. Fixes #1857.
mpegts: ensure init scan completes properly

I was not properly checking completion on table completion and CAT processing
was not marking that table as complete (ever).
Use ONID as CRID authority as last resort.
http htsp: fix status handling. Race condition caused NULL ptr exception. Fixes #1898.
Merge branch 'master' of github.com:tvheadend/tvheadend
support: fix IPTV configuration migration for disabled/unmapped channels
webui: add checkbox selector to all idnode grids. Fixes #1473.
webui: make EPG grid stateful. Fixes #1025.
vendor: add historic DVB API headers

This is useful for validating new code against older versions (and newer).
zlib: fix error on partial compression of files. Fixes #1902.

This occurs where compressing small, already compressd files, typically images.

I could avoid compression of very small (or already compressed) files. But its
simple to keep things uniform and fixing this makes sense anyway!