uhd: added a usrp PC sync option
uhd: added getters for bandwidth setting and range
Merge remote-tracking branch 'jblum/uhd_work'
Merge branch 'master' into next

Conflicts:
	gr-uhd/include/gr_uhd_usrp_sink.h
	gr-uhd/include/gr_uhd_usrp_source.h
	gr-uhd/lib/gr_uhd_usrp_sink.cc
	gr-uhd/lib/gr_uhd_usrp_source.cc