comand line options
-e <energy> 
-n <Number of objects> \
-g <type of gravity> 0=constant, 1=normal(inverse square), 2=inverse, 3=log  4="SHM", 5=super gravity 6=super 3 
-s add sun
-r add rotational velocity
-v add random velocity
-p use solar system planets
-i number of iterations before radnomly selecting another gravity type 

runtine keystroke commands
up/down arrow -> increase/decrease energy per object by 10%
left/right arrow -> switch gravity type up or down
PgUp/PgDn -> increase/decrease number of objects by 10% (or 1 if < 10)
s -> turn on sun
s+shift up/down -> increase/decrease sun mass
r -> add rotatonal velocity
r+shift up/down -> increase/decrease rotational velocity
space -> re-start current 
p - switch to real solar system planets