Update SAB to 0.7.17
- Correct PATH and PID management
Correct download dir permissions for DSM5 for NZBget, SABnzbd, Transmission, ruTorrent
Add saving of user installed plugins in roundcube

Fixes #649.
added headphones-custom SPK
Update unrar to 5.1.2
Fix termination of all sessions in gateone

Fixes #499
Merge pull request #921 from cytec/headphones

added headphones-custom SPK
Wheel
- Create cross-compiled wheels, and store in a wheelhouse
- Use WHEELS var in SPK Makefile to copy cross-compiled wheels, or create pure-python wheels
Add Mercurial SPK using wheel
Change scrypt module to wheel
Merge remote-tracking branch 'upstream/develop' into develop