Adding supercollider packages for raspberry pi and gitignore update

I've updated the .gitignore to also ignore src and pkg folders, as well as package data in any folder below root directory of the repository.

PKGBUILDs and needed patches have been added for community/supercollider aur/supercollider-3.6-git and aur/supercollider-git. They'll now build on and for i686, x86_64 and armv6h (all builds tested on raspberry pi).