Adds Disable function to delete button while delete operation is pending

[finishes: #82655290]

![screen shot 2014-11-24 at 2 48 15 pm](https://cloud.githubusercontent.com/assets/923211/5172996/44fab558-73ea-11e4-8156-444f00b114f4.png)

I am probably wrong but I thought the disabled property is for form elements (fieldset, input, option, textarea, etc). So i used a disabled class since this is used on links and possibly other non form elements.