Feature request: next_eclipse method

@bsipocz requests a `next_eclipse()` function, that calls both `next_primary_eclipse_time` and `next_secondary_eclipse_time` functions and returns a list with both, or even returns a `Table` with a time columns and a P or S flag for the other one.

Locate the existing next_primary_eclipse_time and next_secondary_eclipse_time functions and inspect their return values. The work is done when a new next_eclipse() function combines both eclipse results and distinguishes primary from secondary events, using either the requested list or Table representation.

Written by the indexing model from the issue text.