analog: using VOLK to do conjugate multiply in quadrature demod block.

Even though this requires unaligned loads (in[0] and in[1] are always off cut), it still provides a speedup.
cmake: updated GnuradioConfig script to look for renamed top_block.h file.
runtime: fix use of gr::realtime.
grc: remove "c" key shortcut for create heir action
modtool: Fixes for intial templates of a block.

1. adds '$' to args in the GRC xml <make> tag.
2. sets <+ITYPE+> and <+OTYPE+> for all I/O data types in io_signature and in work functions to be more clear what needs modification.

Conflicts:

	gr-utils/src/python/modtool/templates.py
Merge branch 'maint'
Merge branch 'master' into next
analog: fix quadrature_demod_cf to use std::vector instead of dynamic array
Update revision to 3.6.4.2.
Merge branch 'maint'

Use merge strategy -s ours to skip release commit.
Update revision to 3.6.5.
Merge branch 'master' into next

Used merge strategy -s ours to skip release commits.