Bukkit

Custom commands now show up in Bukkit's /help command
Added basic biome support and an expression 'biome of/at <location>' which cannot be set yet
Added event 'on food level change'
Added event 'on trip'/'on stepping on a tripwire'
Added support for small fireballs
Added alias /sk for the /skript command
Added 'italics' with an s to the available chat styles
Added '<none>' to the available chat styles so that e.g. <%color of dirt%> doesn't print '<<none>>' but nothing.
Added conditions 'is sneaking', 'is sprinting', 'is flying' and 'is sleeping' for players
Added conditions 'is poisoned' and 'is burning' for living entities
Added an optional type argument to damage events (e.g. 'on damage of player')
'Pig zombies' are now properly called 'zombie pigmen'
Arguments of custom commands can now be made completely optional
Changed how arguments with a default value but outside of optional brackets are put inside such brackets
'Entity' cannot be used in projectile hit events anymore, use 'projectile' or 'shooter' instead
Skript will likely not crash the server anymore if it encounters an error
Fixed 'on death of player' not working
Fixed an issue with dead entities
Fixed Bukkit not shutting down Skript's async tasks when reloading
Fixed an error when trying to get the singular of nothing
Fixed an error when displaying the loop 'all items' or 'all blocks', e.g. for an error message
Fixed 'is banned' returning null when displayed
Fixed the general 'is' condition to properly accept a 'than' in comparisions like 'is greather than or equal to'
Fixed enum constants being used incorrectly in variable names

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