Change default home position

I would suggest to set the default home position of the arm nearer to the arm base in future firmware releases. Or even better: let the user define a “home movement sequence” or a “power off movement sequence”, so one could let the arm rest in a user defined “power off”-position, like a holder for the module.

Reason: without power, the arm cannot hold the weight of the laser module at the current default home position and it crashes to the table if power is turned off without moving the arm to a low Y position before. That might damage the laser module or the lens.