This fixes #1301.
Merge pull request #1302 from capooti/issue-1301

This fixes #1301.
Fix ALLOWED_DOCUMENT_TYPES typo in the documentation.
Added some more popular file extensions to ALLOWED_DOCUMENT_TYPES.
add missing import in helpers for remove-deleted option
Merge branch 'master' of https://github.com/GeoNode/geonode
doUpload now returns false so the page does not scroll upwards when Upload is clicked
Merge pull request #1304 from batje/patch-1

doUpload now returns false so the page does not scroll upwards when button is clicked
correct command
Merge pull request #1309 from calvinmetcalf/patch-1

correct command
Fix the quick start url to point to the users tutorial in the docs.
Generate thumbnails for image documents.
Only update thumbnails on creation.
Add event imagery to the base map and default the base map to OSM.

* Default maps to ESPG:3857 vs ESPG:900913.
Revert changes to settings.py in favor of performing those changes in the Yolanda downstream repo.