Figure out how to set home to 1 corner & make working area bigger

[dbenamy]

It seems to think it's at 0, 0, 0 in whatever position it starts up at. It also seems not to allow motion into negative x, y, and z or beyond about 220 on x and y. Figure that shit out!

[dbenamy]

Here's what I'm doing:

• Setting the working area in marlin, Configuration.h. For now I'm using 0-300, 0-300, 0-150. Once we get the table fixed so we can move along the whole thing (Straighten table #7), and install endstops (Add endstops #10) we'll enlarge this to the real size.
• Setting the working area in repetier in the printer settings. I'm making this match the firmware.
• Clicking "home" for 1 axis at a time in repetier. This makes it head towards 0 until it reaches the end stop '''which we don't have'''. When it gets to where I want it to be, I click emergency shutdown (top right). "Stop motors" doesn't work while it's moving. You can also pull the usb to power down the arduino if you're using different software.
• Then I reboot the arduino and (maybe unnecessarily) click "Set Home" so it think it's at 0,0,0/home.

I'll leave this ticket open for the more robust solution once we tackle those other tickets. We'll probably need the more robust solution to not waste metal when cutting plates, and we'll definitely need it for starting from the right place when making holes in tubes.

[dbenamy]

Now that we have endstops, the home command(s) get us to the corner. And I've documented how to set the build area which we can grow once the machine is aligned. Closing.