Stop deploy if `middleman build` fails.
[Cookbook] Add Loading button for asynchronous calls

use ! instead of comparing variable to false

Change settimeout to Ember.run.later

Add spinning button and make buttontext a variable
Merge pull request #1174 from rjackson/do_not_deploy_when_build_fails

Stop deploy if `middleman build` fails.
Merge pull request #1140 from pksjce/spin_button_for_asynchronous_actions

[Cookbook] Add Loading button for asynchronous calls