Display categories by location on posts index page

You can now see all posts by geographic location from the posts index page.
-Removed location link from show page as it's now redundant
-Moved mark as spam button to posts/show
-Moved all posts list to top of locations show page.  Categories appear second.
-Created link to actual post in location/show page.

@ChristopherThorsen @liantics - please take a look and let me know what you think.
Nice use of a constant.