Extend M421 with I and J parameters

Remove SF_ARC_FIX from G5 (Cubic B-spline).
SF_ARC_FIX is a fix for G2/G3 (arcs) where Skeinforge always produced relative instead of absolute coordinates for the endpoint of an arc.
It's very unlikely this is also a problem with Cubic B-splines. More likely is copying from the G2/G3 code.

No compromises for the manage_heater(). manage_heater() will return immediately when there is nothing to do, but needs a constant detaT to work proper.
Calling idle() only every 200ms results in a display update every ~2 seconds - that should be enough.
For the other functionalities in idle() and manage_inactivity() 200ms is a lot but hopefully works.

Speedup sreen update delay
and correct a comment.

A module division by 10 is slooooow. (powers of 2 are fast - but then you can AND a bitmask with the same result)

・Add new translation
・Change translation

Minor DELTA segmentation speedup by pulling calculations out of the loop.

Make sure to only set the fan state once when extruders share a fan

Update forgotten Configuration_DUAL.h

Addressing #3743

Idle during long arcs
to prevent from watchdog resets during high segmented fast arcs.