Change LST and latitude to CachingDms -- this saves a lot of trig calls!

Test case:
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Simulation clock running at 1s per step, centered around USNO NOMAD
milky way artifact patch at the center of milky way, specifically on
Globular Cluster NGC 6569 at Zoom Factor of 32000. Using Horizontal
Coordinates. Projection = 3.

Results:
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Before:
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For the USNO NOMAD catalog under these conditions,
DeepStarComponent::draw spent ~ 0.25s doing ~2233550 trigonometric
function calls per draw ( presumably without updateCoords() being
called -- we call updateCoords only if there's a time slew of more
than 1 solar minute; see StarObject::JITUpdate() )

After:
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After the change, DSC::draw() spent only ~ 0.18s doing only ~1489260
trigonometric function calls.

Note: A call to sincos() is considered to be 2 trigonometric calls.