Refactors grid connections (#3219)

Extracted all checks and subsequent updates to a factory method from the constructor.
Reordered checks to check for nulls before anything else.
Also existing connections before security breaks.
Fixes TileController#checkController() using the wrong position.
Added debug logging for failed connections.
Improved logging.
Inversed boolean so false no longer means security check passed.
Only issue a security break on SecurityConnectionException.

src/main/java/appeng/parts/p2p/PartP2PTunnelME.java

@@ -247,6 +247,8 @@ public class PartP2PTunnelME extends PartP2PTunnel<PartP2PTunnelME> implements I
 					{
 						final TileEntity start = this.getTile();
 						final TileEntity end = me.getTile();
+						
+						AELog.debug( e );
 
 						AELog.warn( "Failed to establish a ME P2P Tunnel between the tunnels at [x=%d, y=%d, z=%d] and [x=%d, y=%d, z=%d]",
 								start.getPos().getX(), start.getPos().getY(), start.getPos().getZ(), end.getPos().getX(), end.getPos().getY(),