Add 'In collection' access panel to metadata panels section.

Closes #35 

![in-collection-ap](https://cloud.githubusercontent.com/assets/96776/3125174/505f42ce-e786-11e3-88c4-64bfe8e27ebb.png)

Extent is not in the index (at least not for MODS records AFICT).  It's possible that we could use the `physical` field in the index (described in #162).

The Finding Aid link will be present in merged collections and won't be available to us until we begin using the index/request handler that returns XML in search results.