test version of ball that just creates and returns a circle
animation of the ball moving over vx and down vy every 100 ms now works
acceleration basically implemented
now storing more natural x, y position variables on the ball object, and the natural-signed velocity
added a css file to style variable displays
function created to add to new array of fns to be called each time step that will update any displayed properties like KE. displayKE function written
wrote displayPE function, debugged switch-case in addDisplayFn so now both KE and PE can be displayed.
removed console.log