@Sheco reported that standalone epoch processing may exclude scheduled
events when the final sumstat epoch runs before. For example, this easily
happens when attempting to do sumstat observations within connection_state_remove().
Delay final epoch processing to zeek_done() instead.
This doesn't deal with the clustered version - this would need something
more elaborate and potentially a mechanism to delay the shutdown of
other cluster nodes until/after sumstat processing completed.
This change allows users to specify an epoch length of 0, which means
that the user manually has to finish the epochs. A new next_epoch
function is introduced to allow users to manually end epochs.
Addresses GH-348
In non-clustered mode, epoch_finished was not called when there was no
data during the epoch.
This behavior does not fit the documentation, and also is different in
cluster-mode, where epoch_finished is, indeed, called after every epoch.
This small change fixes this behavior.
* "bro_is_terminating" is now "zeek_is_terminating"
* "bro_version" is now "zeek_version"
The old function names still exist for now, but are deprecated.
