Update release in homebrew formula and ass MacPorts portfile.
Retire Ubertooth Zero from built binary firmware images
Update links in SourceForge web content
Add python binaries to gitignore
Make it possible to use another toolchain by defining CROSS_COMPILE

It's much easier to use e.g.

CROSS_COMPILE=arm-cortexm3-eabi- make

than to change a dozen lines in two Makefiles.
Merge branch 'master' of github.com:greatscottgadgets/ubertooth