Don't duplicate, just wrap, facility template.

This solves a major part of #103; the rest will be fixed by https://github.com/learningequality/ka-lite/issues/1761 .

The current design for wrapping a template into another app (like embedding the `facility` form inside the `control_panel` breadcrumbs is to use `include_block` to import relevant pieces of code into the including template.

This was not done in the `facility` template; instead, the template was copied.  I made the change to avoid copying code.  In the process of doing that, I made the all-important call into `{{ block.super }}` that was missing and cause #103.

Result:
![image](https://cloud.githubusercontent.com/assets/4072455/2719461/196cb3c4-c561-11e3-81e7-524fe2b552ca.png)

@dylanjbarth would you review?