Add attachment upload modal for resources

:warning: - this requires ooici/coi-services#578 to be merged first

Allows attaching of files to a resource.

![chrome attachment modal](https://f.cloud.github.com/assets/228715/173129/05f6f040-7ad3-11e2-99f0-d6a361ec89a2.png)

Unfortunately we don't have much control over the styling of an `<input type="file"...>` short of hiding it completely and interacting with it on our own, which jquery-fileupload lets you do, but this is a Chrome display issue only.  Firefox looks like this:

![firefox attachment modal](https://f.cloud.github.com/assets/228715/173141/48cade5e-7ad3-11e2-9ac0-cd0f9e1a58f3.png)

On submission, the input is replaced and a progress bar is shown along with the busy indicator used for loading:

![progress bar](https://f.cloud.github.com/assets/228715/173153/b3abe0ba-7ad3-11e2-869a-5bd5653e96af.png)