Add block falls smart event

Also, add Regex event notation.
Add element. as_cuboid, as_plugin, as_inventory

as_inventory isn't tested perfectly as
el@val[player[holder=p@mcmonkey4eva]] is not a valid Element constructor
due to element handling weirdness I don't want to deal with right now.
Merge pull request #642 from mcmonkey4eva/master

Pull request for laziness