use the correct mass of the items for computing the friction force
Fixed: Scale of the crate on skateboard is wrong initially
Fixed: Make it so you can't stack too many items on the stack
updated version numbers for deploy
factored out maxSpeed and show disable bars on the slider when max speed reached
Don't drag into the gray part of the slider if speed exceeded
cleaned up imports
Fixed: Pusher doesn't stay fallen on friction tab when friction >0
fixed friction slider constructor invocation
Converted from svg image for slider knob to code