fix for xls, csv export (fk error, astimezone error)
Merge pull request #56 from bugman80/fix_export

fix for xls, csv export (fk error, astimezone error)
fixes #55
fixes #55, #51
removed get_usermodel() call ad Django 1.4 does not have it
fixes Makefile after removal of casperjs
fixes transaction management
add django 1.7 and trunk to travis
bump 0.6
Merge branch 'release/0.6' into develop

* release/0.6:
  bump 0.6
open 0.7
fixes and enable doctests
fixes issue in mass_update due wrong indentaion