ESC-211 ESC-222 Viewer/Sim comms and outbound data throttle

Cleaned up some of the messaging code that sends the LLSD stats
report off to the viewer.  Added WARNS-level messages when there's
a problem with delivery that will result in a data break.  Users
probably won't care.  Added an outbound data throttle that limits
stats to the 10 regions of longest occupancy.  Should be a
reasonable first cut.