Changed null status provider to prevent NPE when disabling status.
Added code to load a set of focus nodes from the URL query string.
Fixed History entries does not get cleaned up after 1st save.
Merge branch 'space/13.2' of github.com:OpenNMS/opennms into space/13.2
[bamboo] Automated branch merge (from space/13.2:26e86ae4180c32aa4a4b6e965d39d293487ce46b)