Untested! Soft limits, max travel, homing changes, new settings.

- WARNING: Completely untested. Will later when there is time. Settings
WILL be overwritten, as there are new settings.

- Soft limits installed. Homing must be enabled for soft limits to work
correctly. Errors out much like a hard limit, locking out everything
and bringing up the alarm mode. Only difference is it forces a feed
hold before doing so. Position is not lost.

- IMPORTANT: Homing had to be updated so that soft limits work better
with less CPU overhead. When homing completes, all axes are assumed to
exist in negative space. If your limit switch is other side, the homing
cycle with set this axis location to the max travel value, rather than
zero.

- Update mc_line() to accept an array, rather than individual variables.

- Added an mc_auto_cycle_start() function handle this feature.
Organization only.

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