Add block to display conditional check

@BrettASwift @kadst43 Here's a go at making the conditional check visible. It shows the type of scan check block in the HUD trace as the program loops through. I also made the run icon appear to the right of both conditional blocks and number blocks. Not sure if this graphic will be good; we may want something like the m-of-n attached to the run icon idea. I think this is a place to start, though.