Efficiency - world events

Make world event code a bit more efficient by avoiding Regex's
Efficiency - items

Don't search all entities in the world when constructing items - that's
an unused constructor... there are better ways to do that - should be
able to get the item from an EntityItem via e@entity.x tag (if not
possible, a way to do that needs to be added)
Efficiency - Materials

Use a nice map of dMaterials by name to get them, rather than Java
reflection!
Efficiency - other

- precompile regexes
- also, debug cleaning