blocks: add append option to file sink
grc: slash key activates search
modtool: Fixes for in-tree adds, argument parsing (&-bug)
volk: fixed volk rotator kernel to support aligned and unaligned.

blocks: added rotateN to rotator that calls VOLK kernel.
build: don't allow us to build against QWT 6.1 until we can update to support it.
volk: fixed rotatorpuppet for avx.
docs: Clarified how regular and tagged stream blocks interact
digital: OFDM GRC examples are now installed
modtool: Since blocks is needed in 99% of the QA codes, it goes into the template
Merge branch 'master' of ssh://github.com/n-west/gnuradio