Speed up `brute_frequency` by breaking out of the loop early
Speed up `brute_frequency` by breaking out of the loop early

By breaking out of the loop as early as possible `brute_frequency` has to do less iterations, which significantly speeds
up cronlines with second or minute intervals.

The cronline_spec now runs about 35 times faster.

jmettraux/rufus-scheduler,kssminus/rufus-scheduler