Make createorbit() take mean anomaly at epoch in degrees

[vyznev]

This fixes issue #2681. I ran into this issue myself while testing a fix for #2687, so I fixed it and then found this earlier report.

In particular, with this patch, the following function now successfully clones an orbit:

function cloneorbit {
	parameter o is orbit.
	return createorbit(
		o:inclination,
		o:eccentricity,
		o:semimajoraxis,
		o:lan,
		o:argumentofperiapsis,
		o:meananomalyatepoch,
		o:epoch,
		o:body
	).
}

[Dunbaratu]

"Breaking" label added because previously written scripts would have called it with radians.