Fix url_name_args bug.

Fix delete view for motion categories. Add test for custom slide delete view.
Updated Changelog for 1.5b1
Merge pull request #942 from emanuelschuetze/changelog

Updated Changelog for 1.5b1
Merge pull request #941 from normanjaeckel/UrlNameArgsFix

Fix url_name_args bug.
Fix #934: Error in motion import with bad csv file.
Change link in install instruction (Setuptools). Fix #949.
Merge pull request #950 from normanjaeckel/Fix949

Change link in install instruction (Setuptools). Fix #949.
Merge pull request #946 from normanjaeckel/FixImport

Fix #934: Error in motion import with bad csv file.
Merge remote-tracking branch 'upstream/master'