runtime: added ability to name threads, TPB scheduler automatically names each block's thread
blocks: WAV file sink's DTOR is not called, so added 'stop' override to force call of WAV file completion routine (fills in total size in RIFF header)
Merge branch 'maint'
Merge remote-tracking branch 'balint/3.7-2/thread_naming'
Merge branch 'master' of github:gnuradio/gnuradio into pmt_to_python-py2.6-compat