volk: add regex option to profile

If the given regex does not match any substring in a kernel name
then return 0 from run_volk_tests, otherwise execute the tests.
Defaults to a regex of .* to run everything, and no regex which
also runs everything for QA.
digital: HPD now supports time- and other special tags, can mark rx-time of packets
digital: HPD consume-behaviour adapted to allow for trigger jitter
grc: For "No GUI" option, you can now choose which terminal type you like
grc: move xterm pref to Constants.py
grc: format xml fail msg to support python 2.6

In Python 2.6 arguments are needed in the string being formatted, otherwise the error message causes another error.
modtool: added skipping of lib/ and swig/ if sources list is empty
runtime: warn when dropping asynchronous messages due to full asynch message queue, increase default asynch max buffer depth to 8192
Merge remote-tracking branch 'nwest/volk-regex'
Merge remote-tracking branch 'mbant/hpd-timing2'
Merge remote-tracking branch 'gnuradio-wg-grc/grc_config_xterm'
Remove "Bytes to Symbols" block from GRC as bytes_to_syms no longer exists.

(It was removed in commit 45502b80d28e2051f5f7780e0c386147f0976798.)
digital: Fixed example which had invalid default values after changing HPD
Merge remote-tracking branch 'riatsila/patch-3'
Removes qt3 leftovers in qtgui code.
Merge remote-tracking branch 'mbant/oot-modules-without-cpp-maint' into maint
Merge branch 'maint'
logger: setup logger for the tpb scheduler; fixes a swig issue when logger is not present.
blocks: random_pdu (speedup, also allow a byte mask), message_strobe_random (new block, send messages with a known timing distribution)
blocks: random_pdu (allow specifying the length modulo for random pdu lengths)