Use homebrew tap instead of forking homebrew

The standard way to add formula to homebrew is to have a repository named homebrew-_formulaName_ that contains only the formula. These can be used easily by any homebrew user without having to go through the hassle of modifying their homebrew repository to use your fork.

See the added README.md for the usage instructions with `brew tap`.

Tested against nilbus/homebrew-lsusb and working.