pmt: Added float conversion

Added to_float() and from_float(). These are basically aliases
for *_double() with a type cast for when strict typing is necessary
(e.g. SWIG won't accept an f32 value when using from_double()).
Add vector support to abs block. Remove unused num_inputs from xml.
blocks: make tagged stream to pdu output optional
Fix CMake abuse for assembly (.s) files
volk: add feature for json results export
blocks: Added callback to vector source GRC bindings
tags_wip
Fix(?) prune_tags: needs verification
Fix prune_tags
runtime: speed up all the things
Formatting fix-ups
blocks: added example of how to construct and add a tag to a vector_source.
docs: fixed path stripping for binary dirs in doxygen manual.
fec: turning off some debug output.
blocks: deinterleaver will process more than one block at a time for significant speed improvements.
digital: clock recovery fix relative limit
digital: clock recovery delete unused variables
digital: clock recovery more verbose documentation
digital: adapt clock recovery QA
digital: applying same fix of the complex M&M clock recovery block as the float version.