Blockly redux

@BrettASwift @kadst43 This changes the look of the blockly tracing a bit and adds an indicator for repeat loops. Should also take care of the problem where all the blocks would come in at the last second if the game lags.

EDIT: @BrettASwift , I had tried the canvg code -- it looked promising, and I got it to display some blocks, but the display was distorted too much to be useful. I didn't want to spend more time debugging that, so I'm still using images.