Fix remaining issue with autoassigned Block and Item IDs overlapping.
Registry: Block IDs after failing to find a mapping for them
Fix FMLMissingMappingsEvent.get
Registry: Implement support for remapping blocks/items to a new name.
Registry: cleanup, fix missing id error GUI formatting
Fix old 1.7 worlds with broken ID mappings
Registry: allow handling missing blocks/items regardless of the mod id
Merge branch 'master' of https://github.com/MinecraftForge/FML

Conflicts:
	src/main/java/cpw/mods/fml/client/FMLClientHandler.java
	src/main/java/cpw/mods/fml/client/GuiModItemsMissing.java
	src/main/java/cpw/mods/fml/common/FMLContainer.java
	src/main/java/cpw/mods/fml/common/registry/FMLControlledNamespacedRegistry.java
	src/main/java/cpw/mods/fml/common/registry/GameData.java
initial attempt at a better way to ask the user in case of startup issues
Registry: Complain about bogus registrations
Registry: Allow ignoring missing mods from the GUI, with confirm+backup
Registry: Add confirm+backup for automated corrupted id table fixup
Require the user to confirm loading from a backup level.dat
Enable custom gui rendering only as required
Remove unneeded entity spawn debug logging.
Registry: Repair mismatched ItemBlocks as well
Fix a few misc issues
Registry: Fix debug info
Registry: Complain about missing mods when repairing broken worlds
Registry: Reduce console spam
Registry: Protect against putObject misuse, handle duplicate registrations better
Registry: Add support for registering ItemBlocks before their Blocks
Merge pull request #400 from sfPlayer1/master

Fix various registry issues