blocks: better handling of srcid with vector_source blocks.

 - vector_source now adds the srcid of the tag to the actual tag stream.
 - tag_utils' python_to_tag can now be called with just 3 parameters by omitting the srcid; gets filled in with PMT_F.
 - updated vector_source_with_tags example to have tags with and without srcid set.
blocks: benchmark scripts using wrong includes.
Removing use of 'and', 'or', and 'not' for &&, ||, and !.
fec: removed ber_tools; unnecessary and not exported. Replaced compber with call to VOLK's popcount.

Added QA for ber_bf block and provided documentation for it.
Merge branch 'maint'
grc: append blocks path with prefix /usr/local if installed to prefix /usr