Merge pull request #23 from SacNaturalFoods/master

fixed m2m property filters and display fields
Fixed #22
Added error handling to appending the xlsx row
Fixed #26
Added support for sorting dates with None types
Desc sort now works
Readded lower to ignore case in sorts, related to issue #26
2013-04-13 - Jonathan Morgan - changes to support base paths other than web server's root.
Fixed #27 added user_created and user_modified
@kagibbs fyi
Fixed bug in editing a report in admin change view
made TOTALS header row its own row; removed totals labels; spaced totals evenly and aligned with their repspective columns