Ubuntu PPA Updated With Mesa Git + LLVM 3.8 SVN

While Ubuntu 15.10 has Mesa 11.0 and it provides OpenGL 4 support for the Nouveau driver, it doesn't for RadeonSI. The issue is that in Ubuntu 15.10 is still an older version of LLVM that in the AMDGPU LLVM back-end lacks the needed support for OpenGL 4.0/4.1 compliance. Fortunately, a PPA has been updated for Ubuntu Wily with said support...