2016-11-23, Version 3.1.5

Please make sure your database is backed up before applying this upgrade. We are
removing some legacy tables and fields which should not contain any data but
backups should be made as a precaution. Please see the following issue for more
details: #219

• Fix SCM checkins being displayed as "public" (@glensc, #215, #216)
• Make public attachments visible for Viewers (@glensc, #214, #217)
• Removed outdated / unused Impact Analysis code (@balsdorf, #219)
• Re-apply patches number 28 because they could have not been executed (@glensc, #220)