Added an option to the ruler that allows the client to turn off tick marks on the top or bottom of the ruler.  This was done primarily for the Balancing Act simulation, but may also be useful in the Gravity Force Lab sim, see #8.
Added an option to the ruler that allows the client to turn off tick marks on the top or bottom of the ruler.  This was done primarily for the Balancing Act simulation, but may also be useful in the Gravity Force Lab sim, see #8.

phetsims/scenery-phet,phetsims/scenery-phet,phetsims/scenery-phet