Adds support for negotations

As outlined in [Requesting Roles, Enrolling in Observatory, and Requesting Resource Access](https://confluence.oceanobservatories.org/display/CIDev/Requesting+Roles,+Enrolling+in+Observatory,+and+Requesting+Resource+Access)

From the UI a user/org manager is now able to:
- Request observatory enrollment
- Request a role in an observatory
- Acquire a resource in an observatory
- Exclusively acquire a resource in an observatory
- Invite a user to enroll in an observatory
- Invite a user to take a role in an observatory
- Accept/Reject negotiations from the "Open Requests" table in either the Org or User facepages.

### Initiating Requests

Most of these actions are initiated from the page dropdown, and get changed out based on current perms/roles (example):

![Screen shot 2013-04-01 at 6 21 39 PM](https://f.cloud.github.com/assets/228715/325936/bb2bd34c-9b1a-11e2-93d2-a0ff32a810a1.png)

If `Request Role` is picked, a modal is brought up:

![Screen shot 2013-04-01 at 6 23 48 PM](https://f.cloud.github.com/assets/228715/325940/de294c4e-9b1a-11e2-9a85-5b375d287fd4.png)

(these vary based on which action is selected)

### Accepting/Rejecting Requests

Open/closed requests are presented on the facepages of Org/UserInfo.  A user with correct permissions on the correct page may accept or reject a negotiation.  Allowable approved items will feature a new column in their data table:

![Screen shot 2013-04-01 at 6 14 15 PM](https://f.cloud.github.com/assets/228715/325945/2f882b28-9b1b-11e2-9ffd-a21adf097a65.png)

And clicking that row will yield a modal to Accept/Reject:

![Screen shot 2013-04-01 at 6 14 23 PM](https://f.cloud.github.com/assets/228715/325952/3e819222-9b1b-11e2-9f73-f0d1da84d934.png)