add item.has_display

Returns whether the item has a custom display name.
This is to prevent comparing to 'null', and to prevent 'unfilled
attributes' errors.
Add (traits:<trait>|...) to Create command for NPCs.
Merge pull request #524 from Morphan1/master

Add (traits:<trait>|...) to Create command for NPCs.
Merge pull request #522 from mcmonkey4eva/master

add item.has_display
Fix issue with player flag not returning null.
Insert some API for the possibility of denizen auto-registering custom commands. (Still implementing...)
Change dB message scope of unfilled attributes -- now debug instead of error.
Make world events recognize notable inventories.
Add basic meta for reset command.
add matches 'cuboid' to comparable (if ... matches cuboid ...)
Merge pull request #528 from GomaTerzu/master

Make custom items work as ingredients in custom recipes, also small tag-fix to <l@location.inventory>
Add null check for valueOf instead of relying on matches()... gonna be a lot of these!
dMaterial.matches() returns true on any m@ prefixed string
Null check.
Null check.