updating the zsh and macos options. macos not ready for primetime

mac-files/setup_mac.sh

@@ -0,0 +1,20 @@
+install_homebrew() {
+  ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
+}
+
+grab_dependencies() {
+  brew install git
+  brew install vim
+  brew install zsh
+  brew install caskroom/cask/brew-cask
+}
+
+main() {
+  # abort if homebrew is already installed; we don't want to accidentaly stomp on things
+  if hash brew 2>/dev/null; then
+    exit(0)
+  install_homebrew
+  grab_dependencies
+}
+
+main