Added the ability to select which network interfaces and realtime sampling sources are displayed in the Realtime Display view.  This can simplify the UI and reduce CPU use.  Fixed a rare crash bug.  Fixed a bug that prevented recognition of SNMP devices configured to have interface numbers not starting at 1.  Rewrote SNMP functions with a new multithreaded architecture, resulting in faster SNMP device discovery and more distributed core workloads.