Bukkit

0.9 (1.0 pre-release):
    a major update!
    IMPORTANT: now requires ProtocolLib
    fixed a hell load of bugs (here are a few big ones):
        crafted spawners wont stack with normal ones
        fixed command blacklist and op command handling
        fixed inventory glitches when  changing spawner type
        and many, many more...

    improvements:
        added an option to lock commandblocks (and if they are locked hides their command from others)
        made spawners editable via their normal GUI
        hides crafting result if permissions are missing
        removed auto-update (thank you Bukkit :/)

0.8:
    a major update!
    fixed some bugs
    players can now pickup spawners they destroy if they use a pickaxe or iron or higher or a tool with silk touch
    spawners show their name when held
    removed some permissions I felt were redundant
    added permissions for allowing players to break commandblocks/spawners and have them drop
    added option to force the player to hold a pig spawn egg when crafting a spawner (after all, it is a Pig Spawner)
    ...and more that I don't remember :(

0.7.4:
    fixed a bug when trying to craft a spawner in creative

0.7.3:
    removed some debugging stuff I accidentally left

0.7.2:
    first public release

Bug in Minecraft or Bukkit:
    Horse spawners look empty (don't worry, I'm creating a workaround ;D)