gr: added GR_TEST_ENVIRONS to GrTest
Removing gruel from QA python paths.
channels: new frequency selective fading block
Merge remote-tracking branch 'osh/master'
Merge remote-tracking branch 'jblum/gr_test_extra_environs'
channels: selective fading model cleanup
runtime: fix for timer issue that was causing qtgui components to not plot
Merge remote-tracking branch 'osh/master'