channels: setting up callbacks for most dynamic channel model parameters in GRC
analog: fixed Linux assumption, added ifdef to use rand() instead of lrand48() when using MSVC
qtgui: fixed issue with newer versions of QT.

When creating the qApplication in the block, we have to make sure argc>0, argv contains at least one valid character (\0), and they exist over the life of the application.
digital: cleaned up pfb_clock_sync blocks and make sure fff and ccf doing the same things.

Updated QA code to tighten up specs because of better convergence now.
Merge remote-tracking branch 'ncorgan/analog/lrand48_windows_ifdef'
Merge remote-tracking branch 'osh/master'
cmake: update revision to 3.7.1.1
Merge branch 'maint'

Used merge strategy -s ours to skip release commit.
cmake: update revision to 3.7.2
cmake: update revision to 3.7.3git
fft: fixed logpwrfft.py to import new C++ window properly from fft_swig (fixes issue #609 reported by Sylvain Munaut).
fft: put include protections around window.h (fixes issue #610 reported by Sylvain Munaut).
Update revision to 3.7.2

(moved 3.7.2 release to this commit)
Update revision to 3.7.3git