Changes

ReturnFromMoon: fix dtmin bug well enough for now

- the attempt at handling stepping one period into the future was
not doing any useful work at all, now it at least steps dtmin forward
by one period.

- switch to SLP which is about 10x to 100x faster than SQP and gets
all the solve times down under 1000ms.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>
 (commit: 50f1b11)