Merge pull request #76 from billliu1992/master

Added another list to available items, added ability to check in
Altering navigation so that add items and checkouts can be from any page.
Merge branch 'master' of github.com:acm-uiuc/tatt into templates
Merge pull request #78 from eparsons/templates

Changing up the menus a bit
Added templates for adding attributes and attribute values