SetPrinterPosition no longer returns a value

Every function that tracks position implements SetPerinterPosition
Moved GCodeStreamProxy to its own file
Created a new PauseHandlingStream
Wrote a test for same
Fixed the bug with pausing not returning to correct extrusion
Fixed print leveling to pass on the correct offset to SetPrinterPosition
Made sure we always send the shut off extruders on exit
Make agg parse double able to handle a space between the negative sign and the number "- 10".
Put in a test for same.

PrinterCommunication/Io/QueuedCommandsStream.cs

@@ -45,7 +45,13 @@ namespace MatterHackers.MatterControl.PrinterCommunication.Io
         {
         }
 
-        public void Add(string line)
+		public override void SetPrinterPosition(PrinterMove position)
+		{
+			lastDestination = position;
+			internalStream.SetPrinterPosition(lastDestination);
+		}
+
+		public void Add(string line)
         {
             // lock queue
             lock(locker)