Revert "removed unused imports"

This reverts commit b8eef06458836a3c74cc16a7701a14f4b5edeaa7.
Add missing materials to Step. Fixes BUKKIT-4074

When Minecraft 1.4.6 was released, Nether Brick texturing to steps
was added. Minecraft 1.5 added Quartz texturing to steps. When Bukkit
was updated to these version the textures for steps were not applied.

Currently it is not possible to set the texture of steps to quartz
or nether brick. This commit fixes that by adding the respective values
to the allowable materials list.
Fix missing closing bracket in addEnchantment. Fixes BUKKIT-4126

Prior to this commit the message would display as "...(given #, bounds
are # to #". This commit changes that by adding the missing bracket to
the end of the statement. This is strictly a visual error.
Use command block's world for /gamerule. Fixes BUKKIT-3274

In vanilla, gamerules are global, across all worlds. Maps created for
vanilla that use command blocks expect this behavior, which is broken
when they are placed on a world that is not the default world (world #0).

This commit changes that by using the command block's current world when
executing the command, forcing the game rules executed to be executed in
the world the command block is currently in.
Add source encoding to the maven compiler plugin.

This change adds the source encoding to the maven compiler plugin, which
will strictly enforce build consistency on multiple platforms and address
possible compilation issues on some of the source files. The source
encoding unintuitively is system-specified by default.
Deprecate magic values
Make /spreadplayers command work. Fixes BUKKIT-4720
Add new sounds to the Sound Enum. Addresses BUKKIT-4756
Update /say to vanilla behaviour. Fixes BUKKIT-4224

Prior to this commit all /say command output would be a generic "[Server]"
prefixed line. This commit changes that by adding the source into the
message, such as a player. By doing this Bukkit more closely matches
vanilla behaviour and gives a more descriptive message to the client.
Add support for command tab completion in the console. Adds BUKKIT-4168

This commit corrects tab-completion logic to consider non-player command
senders.
Pulling all pending Bukkit-JavaDoc changes
Add SpawnReason for Entity Reinforcements. Fixes BUKKIT-4744
Add missing villager sounds. Addresses BUKKIT-4756
Updated version to 1.6.2-R1.0 in pom.xml for RB.
Updated version to 1.6.2-R1.1-SNAPSHOT for development towards next release.
Correct some magic values. This amends 1f83111208ab3612f384a2e6b65cc28423dc625e
Update Bukkit to 1.6.4
Display correct effect duration in seconds. Fixes BUKKIT-3983
Actually display correct effect duration in seconds. Fixes BUKKIT-3983
Use simple multiplication for squaring. Fixes BUKKIT-4836

This change adds a method to NumberConversions for squaring and
replaces uses of Math.pow(..., 2) with the new method for efficiency
reasons.