Delete mif handling 10806

This adds a UI for notifying a user about partially deleted MIFs.

As yet we don't have the 'dangling' fileset IDs returned from the server after a delete, so there's a placeholder spot awaiting these.

NB: This PR is on top of https://github.com/openmicroscopy/openmicroscopy/pull/1092 and only adds 2 commits currently.

![screen shot 2013-05-07 at 00 12 35](https://f.cloud.github.com/assets/900055/468852/15383fe2-b6a5-11e2-9a09-228196d83593.png)