Add "includes" in categories, cats controllers

Edit index/show views correspondingly
Edit category show page to mimic cat index page
Switch order on admin user index page
refactored cats show page
Additional refactoring of show page

Also changed "is admin?" to "admin?"
Fix partial renderer when review fails.
Move datetime formatting to helper.

Eliminates duplication in the models.
Remove redundant check for nil.
merged in master
merged in adam's changes
Merge pull request #38 from LaunchAcademy/optimize

Optimize