Allow rewind detection when previous zero lag

[jyates]

Rewinds can occur even when the consumer has no lag and its often an indication
that something that gone quite wrong. This change checks for a rewind when there
is any current lag. If a rewind is found in the history of the consumer offsets,
it then checks to see if the consumer has 'recovered' from the rewind. If not,
it is marked as a rewind. If it has recovered, we fall back to the usual
usual status evaluation rules.

Currently the wiki doesn't say anything about REWIND status, but does say:

If any lag within the window is zero, the status is considered to be OK.

However that misses the case where lag can be zero for a while and then jump
back in time. This can occur during a rebalance as consumers drain existing
work (for those that keep a pipeline of work) or due to a broker bug that throws an
Exception when attempting to retrieve the current offsets, causing many consumers
to revert to the beginning of the topic (auto.offset.reset = earliest). The
latter can occur with periodically and unfortunately is a reoccuring theme of
bug (see: KAFKA-9824, KAFKA-9543, KAFKA-9807, KAFKA-9835, etc.)

Addresses #714

[bai]

Thanks for your contribution!