clear agent audio injector after send, don't send if empty
Merge pull request #1067 from birarda/master

clear agent audio injector after send, don't send if empty
First stab at chat circling mechanism.
Base the number of people we include in the circle on whether we would
actually fall in its radius (plus an expansion factor).
Reduce the approach rate.
Another rate adjustment.
Merge pull request #1068 from ey6es/encircle

First stab at chat circling behavior.