Activity period query won't pick up activity close to 0/360

[lfborjas]

If a position is between 359 and 360, or between 0 and 1; the current period of activity query will truncate the examined orb to 360 or 0, rendering one side of the activity shorter than it should. This is merely due to the query needing to be a bit more complicated to account for "choppy" intervals (e.g. between 359.5 and 360 ... UNION ... between 0 and 0.5). With the improved angle calculations in #46, we can now derive these intervals and just need to translated to (somewhat unwieldy) SQL -- write tests!