limit maximum accelerations/velocities

[ianstormtaylor]

I wanted the plotter use the maximum acceleration and velocity when the pen is up. I figured there would be limits in place, so I just put 5000 into the up acc. andup max vel. fields (default is 1000 I believe?). But this resulted in the plotter making some nasty noises and hitting the boundaries and not being aligned properly.

I think Saxi should probably enforce limits on what values are used to not break the plotter. And even better would be having those fields have limits that are reflected in the UI. And even way better would be having a UI that easily allowed someone to choose "the maximum" as an option to not have to think in numbers.