Squash/rebased martin/ofdm-master onto trial merge branch

Conflicts:
	gr-blocks/include/blocks/CMakeLists.txt
digital: fix QA tests for pmt import
analog: minor cleanup for added block
blocks: minor cleanup of added blocks
digital: fixed tagged_stream_mux xml and example GRC app
blocks: adding correct link flags for log4cpp
core: adding default empty tags list argument to vector_source_x.set_data() function to unbreak old calls
blocks: moving copy, endian_swap, head, skiphead, vector_source/sink/insert to gr-blocks.
blocks: moved nop, null source/sink, copy, vector_map to gr-blocks.
blocks: changing vector_insert category location.
Merge branch 'master' of gnuradio.org:gnuradio
blocks: moved lfsr and friends to gr-blocks.
blocks: removing fxpt, nco, vco primitives from gr-blocks.

Have decided to keep all basic math functions in core.
Update revision to 3.6.4.1
Merge branch 'maint'

Used merge strategy -s ours to skip release commit.
Merge branch 'master' of gnuradio.org:gnuradio
blocks: copied plateau_detector from analog to blocks.

This will be removed from gr-analog on next, but I already removed it from any GRC categories to discourage its use.