port b39417b3d4676fb3275aa31be934fe776718504c from Pd-l2ork: experimental improvements to the Linux build to make it compatible with Ubuntu 16.04

*added lyon to default path
(ported manually, left out control file since it was ported in a previous manual port...)

*updated dependencies that reflect rtcmix~ external needs

*forgot to add two files

 *hopefully fixed the remaining conflicts between pd-extended deb and pd-l2ork deb

 *fixed potential package conflict with old pd-extended due to Gem includes. Moved them to /usr/include/pd-l2ork/Gem/ instead of /usr/include/Gem

from pd-l2ork: 640d3c53ad8cd592b1d757b988e27d3ada2b1779

from pd-l2ork: b9cd12d16229acf3a66accc4ad0bdae03d96f19b

from pd-l2ork: a7f382e3d4ffd84c0e7246fdc2d24afca81784f9

 istalls[sic]."
 ee538990d34d4aea0b1757976d8e8dffbeb21a38

0e1938c2d6b3c460fb6eefd027c990fbb36078f9

*further improved naming convention for settings files (default.settings and user.settings), cosmetic improvements to the indexing prompt of the help browser dialog.

*updated file locations and made names more consistent across all folders (everything now uses pd-l2ok instead of pdl2ork). Placed user settings into ~/.pd-l2ork/ folder and renamed to simply settings, placed xapian search database for the browser inside the ~/.pd-l2ork folder.

made shortcuts more flexible in terms of startup (not forcing JACK, which will help on setups that don't want/need JACK backend), as well as providing intelligent menu shortcuts for ALSA and JACK

hopefully improved libglew support due to unfortunately named libs that limit their flexible rollout across different versions of Ubuntu (and likely other distros as well)