Allow missing target in the AttackCommand

To permit cancelling the attack
Make proc[] tags work as actual tags (return dObjects)

Can now use sub-tags after proc[]
Merge branch 'master' of https://github.com/aufdemrand/Denizen
Catch potential click trigger errors

malformed click triggers showed big stack traces - no more of that!
Make NPC location accessible when not spawned

The location is available without an entity, why shouldn't it be
available in a dScript?
Correct a typo in the sign command

Automatic directioning  for WALL_SIGN, not for SIGN_POST.
Fix case sensitivity issues

endswith, startswith, indexof, lastindexof all were case-sensitive...
which is bad.
Fix more case-sensitivity issues

before/after/beforelast/afterlast all were case sensitive
Make element.split case-insensitive as well

I keep finding case-sensitive element tags... we need to follow our own
standards better.
Clean location.matches

The match pattern was causing trouble... a direct check rather than
regex is a lot simpler and more reliable.
Add an EntityPainting property

A way to control paintings, hooray!
Add tag location.normalize

Vector math is always useful
Merge pull request #834 from mcmonkey4eva/master

Pull request for fixing minor things