Finalized Home tab for sellers.

This change set completes the remaining tasks in the [Vendor Homepage: Home Tab Trello Card](https://trello.com/c/J0d9BQdF). Included are server and client side changes for updating item stock, as well as deleting and restoring items and locations. Minor UI updates have also been included. Creating, editing, deleting and restoring both locations and items has been tested, though a sanity check to make sure I'm not going crazy would probably be a good thing. 

**Note:** To run these changes, you will need to install django-undelete. This can be done with the following command:

`pip install git+https://github.com/cpbotha/django-undelete.git`

If the installation yells at you, try again with `sudo`. Sam noticed he was getting some weird warnings on Windows after installing this, but they looked harmless (famous last words)