grc: removed 'old' grc keys from block_tree.

This does not remove the actual GRC files, just how we find them in the block tree structure of GRC.

Renames all blocks not updated to 3.7 style as "(old)" in name.
docs: updating Doxygen categories for all blocks.

Block categories in Doxygen now match where they are in GRC's category tree.
grc: adding sorting ability to GRC category tree.
Merge branch 'master_grc_components'
docs: make Doxygen depend on generated includes before building.
docs: Added a target for trellis generated includes for Doxygen to depend on.
build: only ever include "config.h" in source (.cc) files.
blocks: split blocks swig into 3 files to be swigged individually.

Cuts down on memory footprint of swig. Using blocks_swig.py.in to pull them all in to one file afterwards.
filter: added exception when using interpolating filter with no taps provided.
Merge branch 'maint'
filter: fixed pfb_arb_resampler to handle default taps (None) case.
Merge branch 'maint'
Merge remote-tracking branch 'arya/master_swig_split'
docs: don't depend on generated files from disabled components.
blocks: removing old blocks_swig.i file.
digital: fixes for SNR ests.

set_history: you keep using that word. I do not think it means what you think it means.
Merge branch 'maint'
docs: adds protection from generated files of components not configured.

Also removes a couple warnings in generating docs.
video-sdl: fix typo in .pc file
Merge branch 'maint'