Prioritize powered networks, fixes a glitch with tunnels connecting.

me/Grid.java

@@ -28,6 +28,7 @@ public class Grid implements IGrid
 	HashMap<Class<? extends IGridCache>, GridCacheWrapper> caches = new HashMap<Class<? extends IGridCache>, GridCacheWrapper>();
 
 	GridNode pivot;
+	int isImportant; // how import is this network?
 
 	public Grid(GridNode center) {
 		this.pivot = center;
@@ -228,4 +229,10 @@ public class Grid implements IGrid
 		}
 	}
 
+	public void setImportantFlag(int i, boolean publicHasPower)
+	{
+		int flag = 1 << i;
+		isImportant = (isImportant & ~flag) | (publicHasPower ? flag : 0);
+	}
+
 }

me/GridConnection.java

@@ -62,7 +62,7 @@ public class GridConnection implements IGridConnection, IPathItem
 				GridPropagator gp = new GridPropagator( a.getInternalGrid() );
 				b.beginVisition( gp );
 			}
-			else if ( a.myGrid.size() > b.myGrid.size() )
+			else if ( isNetworkABetter( a, b ) )
 			{
 				GridPropagator gp = new GridPropagator( a.getInternalGrid() );
 				b.beginVisition( gp );
@@ -82,6 +82,11 @@ public class GridConnection implements IGridConnection, IPathItem
 		sideB.addConnection( this );
 	}
 
+	private boolean isNetworkABetter(GridNode a, GridNode b)
+	{
+		return ((Grid) a.myGrid).isImportant > ((Grid) b.myGrid).isImportant || a.myGrid.size() > b.myGrid.size();
+	}
+
 	@Override
 	public void destroy()
 	{

me/cache/EnergyGridCache.java

@@ -27,6 +27,7 @@ import appeng.api.networking.events.MENetworkPowerStatusChange;
 import appeng.api.networking.events.MENetworkPowerStorage;
 import appeng.api.networking.pathing.IPathingGrid;
 import appeng.api.networking.storage.IStackWatcherHost;
+import appeng.me.Grid;
 import appeng.me.GridNode;
 import appeng.me.energy.EnergyThreshold;
 import appeng.me.energy.EnergyWatcher;
@@ -379,6 +380,7 @@ public class EnergyGridCache implements IEnergyGrid
 			return;
 
 		publicHasPower = newState;
+		((Grid) myGrid).setImportantFlag( 0, publicHasPower );
 		grid.postEvent( new MENetworkPowerStatusChange() );
 	}