core/digital: added more logging
uhd: updated usrp_spectrum_sense with frequency readout
Merge remote-tracking branch 'mbant/morelog3'
core: added boost/format.hpp to logger header for easy use when formatting strings in log messages.
digital: OFDM carrier allocator can now handle the sync words
digital: made the tagging description for packet header gen more explicit
docs: More and better docs for tagged stream blocks (and some childs)
Merge remote-tracking branch 'mbant/sword2' into next
Merge branch 'master' of gnuradio.org:gnuradio
Merge remote-tracking branch 'mbant/headertags'
Merge remote-tracking branch 'mbant/taggedstreamdox'
Merge remote-tracking branch 'm0mik/uhd_usrp_spectrum_sense_freq_readout'
Merge branch 'master' into next

Conflicts:
	gnuradio-runtime/include/gr_logger.h
	gr-digital/lib/packet_headergenerator_bb_impl.cc
	gr-digital/python/ofdm_txrx.py
	gr-digital/python/qa_ofdm_txrx.py
	gr-digital/python/qa_packet_headergenerator_bb.py
	gr-uhd/examples/python/usrp_spectrum_sense.py
runtime: fixing missing includes from previous merge conflict.
digital: adding sync_word input to OFDM QA code.