Remove 0install mac docs and tweak homebrew
Remove 0install mac docs and tweak homebrew

Homebrew instructions are much easier than 0install, so no need to confuse people.
zanata/zanata-platform,zanata/zanata-platform,zanata/zanata-platform,zanata/zanata-platform,zanata/zanata-platform,zanata/zanata-platform,zanata/zanata-platform