Ubuntu mate for rapsberry pi improvements

Hardware acceleration might be addressed in a kernel 4.4:


One problem with PPAs is that explicit permission is needed for developers to compile ARM packages, which is why many may only build for i386 or amd64. You can instead however, compile and package up the ARM build to a deb, which can be shared along with a copy of the source code (depending on the license, that might be compulsory).