play audio when spark appears, see #36
removed debug comment
When a spark is triggered, only send electrons in the body to the spark, not new electrons, see #27
Removed memory allocation in animation loop
added credits, see #40
removed the white arrow, see #41
Don't show appendage borders if they are being dragged during reset all, see #45
updated version
Test for spark in every step so that newly added electrons can be assigned to exit if the threshold is still exceeded, see #27
updated version to 0.0.0-dev.17
Stop electrons from going to the finger if the threshold (electrons / distance) not exceeded, see #27
updated version to 0.0.0-dev.18
Tuned the distance threshold to make sure the spark will shut off more quickly when the finger moved far from the doorknob, but not soo small that electrons can leak out of the body, see #27
updated version to 0.0.0-dev.19
when grounded, discharge all electrons, see #27
updated version to 0.0.0-dev.20
recorded new audio, see #49
updated version to 0.0.0-dev.21
changed strings to match format specified in https://github.com/phetsims/chipper/issues/43
removed randomness so we can try to ensure electrons stay in the body shape in case the spark stops