Issue #34: Change osx setup script to be configurable

default.config.yml

@@ -76,3 +76,5 @@ homebrew_cask_apps:
 mas_installed_apps: []
 mas_email: ""
 mas_password: ""
+
+osx_script: "~/.osx --no-restart"

tasks/osx.yml

@@ -1,5 +1,5 @@
 ---
 # TODO: Use sudo once .osx can be run via root with no user interaction.
 - name: Run .osx dotfiles.
-  shell: ~/.osx --no-restart
+  shell: "{{ osx_script }}"
   changed_when: false