OpenNMS Meridian 2015.1.9 Released

Release 2015.1.9 is the tenth release of OpenNMS Meridian 2015.
It contains a keyboard-navigation fix and a few documentation/date updates.
The codename for 2015.1.9 is MIST.

Bug

• • Tweak Mattermost notification docs not to specify a channel (Issue NMS-9362)
  • Inconsistent handling of keyboard navigation on top menu (Issue NMS-9867)
  • Copyright dates need a bump for 2018 (Issue NMS-9871)