Minor: move EntityDamageEvent "tool is null" message to HIGH as it's served it's purpose, and ignore message completely if due to TNTPrimed.

* PrimedTNT (and soon to be TNTMinecarts) don't have a tool (always?) so can't get the attack range.
* Left the message there in case something else causes the lack of a tool.
Change: a left click on a mob is now handled as a "HIT" action/trigger.  "LEFTCLICK" still supported (automatically changed to HIT if it's configured on a mob)

* For the sake of consistency and makes logical sense.
Release 2.8b.299