digital: HPD fixes (burst ID tags are no more propagated; buffer sizes are halved to est. max output size)
modtool: bugfixes for in-tree operation (include paths, license, cmake editing)
volk: naming error between orc file name and kernel name.

Fixes bug #583.
volk: explicitly casting tolerance to float or unsigned int for passing to fcpmare or icompare in QA tests.

On ARMs, passing tol as a float to icompare that expects an unsigned int caused improper casting. Fixes bug #582.
blocks: loosen restriction on damping factor in control_loop class.
digital: updated qa_mpsk_receiver to have similar tests in test01 and test02.

This is based of and should fix issue #569.
digital: on 32-bit machines when M=4 using single-precision float was causing k=1. Using double-precision calculation here to avoid possible confusion and errors
blocks: fix pdu_to_tagged_stream when saving leftover items
Merge remote-tracking branch 'martin/hpd-modtool-fixes' into maint
digital: fix CID 1090058 and 1043272 in constellation
digital: Fix CID 1043268 and 1043271
grc: fix search entry focus (again)
docs: fixed doxygen warning.
docs: fixed exploring-gnuradio examples and added to doxygen manual.
pmt: added class comparator to rename comperator (to be removed in 3.8).
blocks: prevent alowing more input streams than this block uses.
docs: fixed/modifying/adding documentation for blocks a-l.
digital: fixed warnings about order of initializing variables in constellation.
cmake: ensure GrPython is included before using methods from it in FindICE.cmake - needed when including only FindICE from OOT modules
cmake: fixes for Apple (specifically; clang generically) to handle some missing AVX instructions.