Endless loop in ephem/__init__.py

[tramtram]

There is an endless loop in line 461 in the file init.py. This appear in very very rare cases.

The moon sets again a few minutes after sunrise, it actually just licks the horizon and moves almost horizontally, it's stupid to determine exactly when it happens, when it has to be precise to fractions of a second.

Please add counter to the loop.

Thank you very much

Brano