Voxel/Particle Server Scaling Work

* Application only sends new octree queries if the view has changed or its been a significant elapsed time since last query - closes #1273
* convert a bunch of qString.toLocal8Bit().constData()  to qPrintable(qString) in Stats Dialog
* add full scene stats for number of packets, bytes, pps in last full scene
* correctly handle detection of lost packets vs out of order packets - closes #2264
* have domain-server suppress the messages about Assignment::AgentType waiting for jobs (which was overflowing the logs and causing servers to run out of disk space).
* cleanup OctreeSendThread.cpp's use of isFullScene, which had a duplicate variable calculated twice from same input.
* deleted some unused headers
* added LOD description to overlays - closes #2265