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
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
Merge pull request #1084 from birarda/master

fix missing link to starfield implementation files
fix unix build buster for starfield
fix for audio-mixer crash with node from DS
fix audio send to wrong socket