fix getters on solar Time class

The various retrieval methods on Time were supposed to be dynamic properties, not methods.

Major refactor

This release is a substantial refactor to the interface, attempting to more closely mimic how this library is actually used, rather than what the math looks like.

Bring deps in line with API

This PR makes no code changes, simply bumps the dependencies such that they're inline with API. (The diff is monstrous because of the switch from JSHint to ESLint.)

Add millisecond conversion methods

Adds:

astro.ms_to_julian()
astro.julian_to_ms()

Initial tagged release.

v1.0.1

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