Begin converting doEvents to take dPlayers

dPlayers are needed, most importantly for OfflinePlayers but also just
to fit Denizen standards.
Unfortunately, we can't just have a direct replacement event as dPlayers
and Players are very similar objects in the eyes of Java, and this must
be done in a two-part conversion.
For now, a secondary function using a placeholder event is in use so the
original event can be removed throughout Denizen, Depenizen, and other
API-using projects.
Once that is done in it's entirely ,the placeholder-int function will be
marked deprecated and the old function will be changed to take a dPlayer
instead, and that will be used, until a final commit removes the
placeholder-int function.
Fix Wither Skull entity velocities

Wither skulls use a different function to do exactly the same velocity
handling. I have no idea why. Either way, this will automatically use
the side function for wither skull entities.
Fix running queues with a short delay

Due to the weird way programming languages do math, decimals are only
counted if you tell them to be counted... this will now count them
properly, permitting delays that aren't full-seconds.
Change util.date.time.24hour to twentyfour_hour, fixes #708

using numbers as the start of a tag name is a poor idea in general and
doesn't work at all for this case (outdated util tag handling)
Technically a breaking change but the tag didn't work at all for a
*long* time, so...
Allow tags in the save: argument

Tags are now parsed ++ proper debug to see what the final save-name is.
Handle horse styles in the color property

It now handles spots, and donkeys, and etc. automagically.
Add cancelling server commands

Be very careful with this -- don't block the stop command unless you
really hate yourself.
Allow empty context.cuboids in events, fixes #711

For some reason the context would only add if there were actual cuboids
involved. It now adds as an empty list in that case.
Merge pull request #706 from mcmonkey4eva/master

pull request for unusual temporary work arounds