Conform to Denizen standards

Hurray for +1 -1 slots
Allow "player clicks" in "player (<click type>) clicks block"
Add dPlayer fake_experience and fake_health mechanisms
Improve inventories

Equipment is just... Odd.
Sometimes it decides to work, sometimes it doesn't.
As far as I can tell, it only works for opening and viewing, not actual
adding/removing (not sure about modifying the itemstacks?).
But anyway, I'm committing this before any more pile-ups happen
[BREAKING] Add ItemPotionEffects property, remove redundant EntityPotion tags

This pretty much sane-ifies potion stuff.
It also allows custom potion effects.
For example:
- give i@potion[potion_effects=poison,3,1d]
Add ItemSplash property

This allows you to create splash potions.
- give i@potion[potion_effects=poison,3,1d;splash=true]
Add <i@item.is_potion> tag
Merge pull request #680 from Morphan1/master

Pull Request for all Morphan kind