Refactored AEConfig (#2633)

Added a singleton getter instead the public field.
Reduced all fields to private.
Replaced field access with getters.
Added setters where necessary (Dimension/Biome Registration)
Added config options to disable more features.
Splitted Enum name from the config key.
Changed FacadeConfig and Networkhandler similar to AEConfig.init().

src/main/java/appeng/bootstrap/ItemDefinitionBuilder.java

@@ -147,7 +147,7 @@ class ItemDefinitionBuilder implements IItemBuilder
 	@Override
 	public ItemDefinition build()
 	{
-		if( !AEConfig.instance.areFeaturesEnabled( features ) )
+		if( !AEConfig.instance().areFeaturesEnabled( features ) )
 		{
 			return new ItemDefinition( registryName, null );
 		}