Update to 1.15

Most of the port is pretty simple. The main problems are regarding
changes to Minecraft's rendering system.

 - Remove several rendering tweaks until Forge's compatibility it
   brought up-to-date
    - Map rendering for pocket computers and printouts
    - Item frame rendering for printouts
    - Custom block outlines for monitors and cables/wired modems
    - Custom breaking progress for cables/wired modems

 - Turtle "Dinnerbone" rendering is currently broken, as normals are not
   correctly transformed.

 - Rewrite FixedWidthFontRenderer to to the buffer in a single sweep.
   In order to do this, the term_font now also bundles a "background"
   section, which is just a blank region of the screen.

 - Render monitors using a VBO instead of a call list. I haven't
   compared performance yet, but it manages to render a 6x5 array of
   _static_ monitors at almost 60fps, which seems pretty reasonable.

src/main/java/dan200/computercraft/shared/proxy/ComputerCraftProxyCommon.java

@@ -11,7 +11,6 @@ import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.peripheral.IPeripheralTile;
 import dan200.computercraft.core.computer.MainThread;
 import dan200.computercraft.core.tracking.Tracking;
-import dan200.computercraft.shared.Config;
 import dan200.computercraft.shared.command.CommandComputerCraft;
 import dan200.computercraft.shared.command.arguments.ArgumentSerializers;
 import dan200.computercraft.shared.common.DefaultBundledRedstoneProvider;
@@ -36,7 +35,6 @@ import net.minecraft.world.storage.loot.conditions.LootConditionManager;
 import net.minecraftforge.event.TickEvent;
 import net.minecraftforge.event.entity.player.PlayerContainerEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
-import net.minecraftforge.fml.client.event.ConfigChangedEvent;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
 import net.minecraftforge.fml.event.server.FMLServerStartedEvent;
@@ -127,12 +125,6 @@ public final class ComputerCraftProxyCommon
             }
         }
 
-        @SubscribeEvent
-        public static void onConfigChanged( ConfigChangedEvent.OnConfigChangedEvent event )
-        {
-            if( event.getModID().equals( ComputerCraft.MOD_ID ) ) Config.sync();
-        }
-
         @SubscribeEvent
         public static void onContainerOpen( PlayerContainerEvent.Open event )
         {