fix to rescue errors on connect correctly not to be stuck node thread
Fix to specify abort_on_exception for nodewatcher thread
 * This thread's stuck is extremely dangerous for secure-forward
 * If secure-forward is a key part of Fluentd instance, stuck of nodewatcher is fatal error
fix to use fixed node size to show node size does not change explicitly
remove extra begin-rescue to use abort_on_exception
Fix timeout detection
 * This is serious and awful mistake: Time.now is always larger than past time...
v0.2.1
improve log message to show node connectivity explicitly