debuild update: update to nw.js 0.15.4, remove DejaVu font from package for which we have a dependency anyway.

port agraef's commit from Pd-l2ork: debuild: more permission fixes. commit 7a1dd816b0fcbb42f733e7e715d3323d15608d33

port agraef's commit from Pd-l2ork: debuild: sanitize file permissions. commit 22edd363ff166125578cf1465a297c417c4e3665

port agraef's commit from Pd-l2ork: Adjust debuild so that it uses 'tar_em_up.sh -B -n' to do the staging. commit 835fa21ca36b5987a4bde01c7595293ff4c09abd

port 79acee0a55fc5941685401e4c26c1ff741a10c62 from Pd-l2ork: Update debuild after wiringPi is now a submodule.

port 247e970d91012986083a696b742cdcb72bb829ec from Pd-l2ork: Add wiringPi sources to make disis_gpio build on Launchpad again

port 93c4266dcbd1444af39a60e9638484eb482d9451 from Pd-l2ork: Update debuild packaging system for latest pd-l2ork source and Ubuntu 16.04