modtool: dashes no longer allowed in modnames at all (fixes #619)
Update revision to 3.7.2.1
Fix a typo that prevents the Max block from working in GNU Radio Companion
when its IO Type is set to Short.
volk: removing duplicate entry for volk_8i_convert_16i.
volk: using union for float to int conversion in volk_32f_invsqrt_32f.

Removes warning about type-punned pointer. Also, produces noticeable speed increase using GCC, though slightly slower with clang.
math: fixes fast_atan2 float==0 check.

runtime: adds math functions to swig to make available as gr.function.
runtime: Moved QA code that uses blocks to the gr-blocks component.
digital: fixed for d{b,q}psk to actually use differential modulations.
cmake: search the install prefix for cppunit incase it is installed there
utils: fix typo in gr_plot_const
runtime: Minor cosmetic typo and whitespace corrections.

Signed-off-by: Moritz Fischer <moritz@ettus.com>
gr-modtool: fix typo in howtoConfig.cmake
digital: typo fixed to "sps" (samples/symbol).
volk: clang/linux/avx fix
cmake: findIce fix (search $CMAKE_INSTALL_PREFIX first for source installed 3.5 needed for clang)
qtgui: fixed issue preventing gr-qtgui build if Python-dev is not installed (ENABLE_PYTHON=False).
blocks: bug fix in tagged_stream_to_pdu which was causing memory corruption and missing/zeroed trailing ends to pdu data vectors
qtgui: more fixes needed to turn on/off python properly for sip calls.
volk: cleaned up 32fc_x2_dot_prod_32fc code. Improved results; fixed on OS X.

- Added unaligned versions of kernels.
- Fixed issues with tail handling
- Use _mm_setzero_ps instead of subtracting to zero out values
volk: fixed issue with size_t comparison of std::string function (compare against std::npos, not -1).
filter: fixed issue with resampler using buffer size information (always a mistake).

The intent was to ask the scheduler for the maximum amount of data. Now, it plays it safe by asking for just enough the next time. Performance tests show it works well.