Make dLocations get identified as notables if they have the same block coordinates as a notable, not if they have the exact same coordinates

Allow optional "l@" identifiers in "on player walks over <notable>"
world event. Make that event get triggered when the player reaches that
location, not when the player departs it. Fix space typo in inventory
clicking event. Unminify methods used in Experience command so they can
be examined and fixed more easily.