View calculations prototype

The first prototype of https://bugs.launchpad.net/oq-platform/+bug/1236843.

The UI looks awful, the workflow is rough, the code is ugly, and it needs a lot of work. This is just a prototype, and I just wanted to get the work-in-progress reviewed before anymore work is done on it.

Needs https://github.com/gem/oq-platform/pull/101 and all of its dependency branches.