add ping/reply to assignment-client servers
don't send audio to nodes who don't have an active socket
don't attempt to send in UDPSocket with NULL destAddress
Merge pull request #1081 from birarda/master

fix pinging of agents in broadcast to nodes, audio injection crash
add debug to test hole punching
Merge branch 'master' of github.com:worklist/hifi into assignment
increase the ping interval
bring ping interval back to 1 second
add packet receive debug
add debug to AvatarMixer, not AudioMixer
remove crazy debug from testing
remove an infamous birarda extra g
remove the debug in Application.cpp
Merge pull request #1082 from birarda/assignment

ping/reply from servers for hole punching
Starfield modification to randomly generate stars

Starfield now generates stars at startup rather than load them from the
server - approx. 50msec to load 50,000 stars.

STAR_COLORIZATION const in Generator.cpp is used to defined how
colorful the stars should be.

STARFIELD_NUM_STARS and STARFIELD_SEED sets the number of stars and the
random number seed used to generate the starfield.
Merge pull request #1083 from lordwaym/mod-starfield

Starfield modification to randomly generate stars
fix missing link to starfield implementation files