first revision of sundial

Works with current uploader code, not yet modified to include needed tideline functions.

@jh-bate or @cheddar please review. @cheddar would like me to merge and tag this and have the uploader depend on it before merging the uploader branch where I've removed the moment dependency and replaced it with sundial methods.
I see that this one is just passing them through to moment, so maybe not as big of a deal, but it still seems useful to have a test or two that solidifies the directionality of numerical offsets just to be safe.