Add full block wired modems

These act similarly to conventional wired modems, but with the advantage
that they are a full block. This means they can be attached to
peripherals which are not solid (such as chests). Further more, as they
do not have a direction, they allow wrapping peripherals on all 6 sides.

It's worth noting that wired modems do not require a cable - they will
automatically form connections to adjacent network elements when placed.

src/main/java/dan200/computercraft/client/proxy/ComputerCraftProxyClient.java

@@ -115,6 +115,7 @@ public class ComputerCraftProxyClient extends ComputerCraftProxyCommon
         registerItemModel( ComputerCraft.Blocks.commandComputer, "command_computer" );
         registerItemModel( ComputerCraft.Blocks.advancedModem, "advanced_modem" );
         registerItemModel( ComputerCraft.Blocks.peripheral, 5, "speaker" );
+        registerItemModel( ComputerCraft.Blocks.wiredModemFull, "wired_modem_full" );
 
         registerItemModel( ComputerCraft.Items.disk, "disk" );
         registerItemModel( ComputerCraft.Items.diskExpanded, "disk_expanded" );