Show the unique species and dbhs in popup

Previously we were showing the whole grid... but that got messy quite
quickly. The new approach is to just show to lists: "Species" and
"Classes" that are in this polygon and let the user click through for more.
Merge pull request #133 from ahinz/bug/update-popup-text

Show the unique species and dbhs in popup
Open polygon view/edit link in a new tab
Add descriptions to models
Update submit button text for polygon photo upload
Provide a horizontal scroll bar if there are too many DBH Classes
Expose DBH Classes and Entries in the admin

Polygons themselves are not included in the admin because testing showed
that they made the site too unstable to be of any real use.
Merge pull request #135 from ahinz/bug/polygons

Bug/polygons
Add audit support to polygon models
Add helper functions for handling polygon histories
Add url/view/template for recent edits admin page
Modify polygon update view to populate audit trail
Update polygon detail to show recent edits
Merge branch 'topic/recent_polygons' into v1.3

Conflicts:
	polygons/models.py
Edit styling on polygon popup for results map
Style polygon view/edit pages, add highlight on polygon popup rows
Merge pull request #137 from azavea/topic/polygon_styling

Polygon UI Styling
This random code was included in the original version.

Seems useless and wasteful. Bringing out the Daleks....
Fix FF bug with tables not clearing
Remove docstrings that don't provide detail