Add logging/LogAgent from CraftBukkit 1.5.1 (renamed MCP class ConsoleLogManager)

This class was renamed in MCP from 1.4.7 to 1.5.1:

net/minecraft/logging/LogAgent - MCP in 1.5.1
net/minecraft/server/dedicated/ConsoleLogManager - MCP in 1.4.7
net/minecraft/server/ConsoleLogManager - CB in 1.5.1 and 1.4.7
Fix duplicate logging with LogAgent

Fixes logging both to CB and FML, causing two log entries for
each log line. Note this was already fixed in 1.4.7, porting
the same fix to 1.5.1 (logging only to CB) in MCP's
net/minecraft/logging/LogAgent class (formerly known in 1.4.7
as net/minecraft/server/dedicated/ConsoleLogManager). Both
versions of CB name this class net/minecraft/server/ConsoleLogManager.
Add packaged MCP -> obfuscated mapping
Exclude argo from obfuscated mappings
Remove org.bukkit from transformer exclusions in preparation for runtime deobf

org.bukkit.craftbukkit (OBC) contains NMS references which need to be
deobfuscated by FML for runtime deobfuscation. However runtime deobf is
disabled for now, requires fixing https://gist.github.com/agaricusb/5234401 #643