Bukkit

Added expression 'altitude of <location>'
Added expression 'x/y/z-coordinate of <location>'
Improved error messages a bit
Improved arithmetics to use 0 if somehthing isn't set, e.g. {unset variable} + 1 now evaluates to 1.
Fixed local variables
Fixed an error when using 'target' without specifying an entity type

The damage in damage events is still the raw damage, i.e. without any armour/critical/enchantment modificators applied.
If no world is specified in a periodical event no errors are printed if one uses the event-world (e.g. by using 'time' instead of 'time of <world>'), but it will fail silently when the script is executed.

see also: https://github.com/Njol/Skript/issues?labels=bug&page=1&state=open