Fixed bug in calculation of derivative filter taps.
Merge branch 'master' of git.gnuradio.org:gnuradio
grc: revert ce52bd370 fixes problem with order
grc: allow multiple ports with varying nchan
grc: fix port names (index relative to port type not absolute)
grc: white background
grc: white blocks for nicer screenshots
blocks: add append option to file sink