Bukkit

Age of converted horse will match the age of the original one, so you won't get new baby horses spawns from old adult once (and vice versa)
Converted horses will NOT be auto-tamed by who converted them any more.
Horses shouldn't drop leather/bones/rotten flesh anymore when getting converted
Fixed wrong player message when the player has insufficient XP to convert a horse
As Minecraft tries to make the player ride the horse and teleports them to rider position (changing pitch and yaw as well), teleport them back if the horse gets converted (and riding fails)