runtime: restoring sanity to pmt.is_blob()
filter: Adding filterbank_vcvcf, a filterbank where all taps are explicitly set.
Add HDLC deframer to gr-digital. Input unpacked bits, output PDU binary
blobs.
fix numpy to pmt uvector conversion
filter: Adding hierarchical pfb channelizer.  Useful if pfb_channelizer is bottle-neck since it splits it into multiple blocks.
blocks: hide 'ignore tag' param for 'throttle' block in GRC if it's the default value (i.e. old look before param was added)
digital: added 'byte' IO format
blocks: added 'MTU' (buffer size) & 'no_delay' params to 'tcp_connection' (no longer uses fixed buffer)
blocks: added 'MTU' and 'tcp_no_delay' params for 'socket_pdu' (and GRC option), applied MTU (buffer size) to TCP/UDP send, separate TCP/UDP server endpoint resolvers for empty/0.0.0.0 Host param (listen on all interfaces)
Whitespace clean-up.
cmake: updated max ver for FindQwt to 6.2.0 (Qwt compiled direct from their source tree worked with trondeau's qt_number_sink test FG)
filter: Adding grc files and example for hierarchical pfb channelizer and generic filterbank.
filter: Remove debugging block from channelizer_hier_ccf.
Add matching HDLC framer. Fix deframer max/min.
Add QA code to HDLC framer/deframer.
Merge remote-tracking branch 'osh/pmt_fix'
Merge remote-tracking branch 'bistromath/hdlc'
Merge remote-tracking branch 'balint/3.7-1/tcp_connection_mtu_no_delay'
Merge remote-tracking branch 'balint/3.7-1/header_payload_demux_byte_type'
Merge remote-tracking branch 'balint/3.7-1/throttle_grc_hide_ignoretag'
Merge remote-tracking branch 'balint/3.7-1/socket_pdu_improvements'