Touch event tweak

Some minor tweaks I noticed while trying to set up a draw instance embedded in an iframe and use it in different browsers and on android devices. 
* chmod +x safeRun.sh for the init.d script
* added preventDefault() to mouse events to stop screen from scolling while drawing in chrome browser on android devices. (Still having some issues interacting with an embedded draw in the default android browser, but it seems to work great on android in Chrome and Opera)
* provided default for rgb_array if it comes back as undefined. (Was causing a crash when loading embedded draw in firefox on windows, but not in chrome)