Less scary message with Ctrl-C, remove gcode viewer for android

Let's try this again, this time on the devel branch! 

On all android devices I've tried this on, the gcode viewer crashes the browser very hard because there's not enough RAM on the devices to load up large gcode files. This short snippet simply removes the gcode-related elements if it detects an android browser.

While I realize that this is sub-optimal in the off chance you're running android on a full blown computer, all devices I've tried this on from a brand new Moto X to a Nexus 10 tablet has managed to crash after loading the gcode viewer. Thoughts on this change?