Use utility method for team-join display. Fixes BUKKIT-3997

The method to make a string from a collection of strings already exists
and should be used when adding multiple players to a team.
Consider arguments to team leave properly. Fixes BUKKIT-3994

Two checks to argument length were changed to properly consider if the
sender is a player instead of an off-by-one logical error.
Consider first player name in leave command. Fixes BUKKIT-4051
Correct 1.5 material data. Fixes BUKKIT-4004, BUKKIT-3785
Fix off-by-one error in DyeColor. Fixes BUKKIT-3938
Pulling all pending Bukkit-JavaDoc changes
Updated version to 1.5.1-R0.2 in pom.xml for BETA.
Updated version to 1.5.1-R0.3-SNAPSHOT for development towards next release.
Add inverted flag support to TrapDoor. Fixes BUKKIT-3390
Update Bukkit for Minecraft 1.5.2
Move world generator warning to CraftBukkit. Fixes BUKKIT-2565
Updated version to 1.5.2-R0.1 in pom.xml for BETA.
Updated version to 1.5.2-R0.2-SNAPSHOT for development towards next release.
Pulling all pending Bukkit-JavaDoc changes