Makes Coordinates more Structy (#417)

More readonly-ish and less write-ish

Author: clusterfack

SS14.Client/Placement/Modes/AlignSnapgridBorder.cs

@@ -60,7 +60,7 @@ public override bool Update(ScreenCoordinates mouseS)
                 (float)Math.Round((mouseCoords.Y / (double)snapsize), MidpointRounding.AwayFromZero) * snapsize);
 
             //Convert back to original world and screen coordinates after applying offset
-            mouseCoords.Position = mouselocal + new Vector2(pManager.CurrentPrototype.PlacementOffset.X, pManager.CurrentPrototype.PlacementOffset.Y);
+            mouseCoords = new LocalCoordinates(mouselocal + new Vector2(pManager.CurrentPrototype.PlacementOffset.X, pManager.CurrentPrototype.PlacementOffset.Y), mouseCoords.Grid);
             mouseScreen = CluwneLib.WorldToScreen(mouseCoords);
 
             if (!RangeCheck())

SS14.Shared/Map/Coordinates.cs

@@ -14,19 +14,11 @@ public struct LocalCoordinates
     {
         public readonly int GridID;
         public readonly int MapID;
-        public Vector2 Position;
+        public readonly Vector2 Position;
 
-        public float X
-        {
-            get => Position.X;
-            set => new LocalCoordinates(value, Position.Y, GridID, MapID);
-        }
+        public float X => Position.X;
 
-        public float Y
-        {
-            get => Position.Y;
-            set => new LocalCoordinates(Position.X, value, GridID, MapID);
-        }
+        public float Y => Position.Y;
 
         public IMap Map => IoCManager.Resolve<IMapManager>().GetMap(MapID);
 
@@ -90,19 +82,11 @@ public bool InRange(LocalCoordinates localpos, int range)
     public struct ScreenCoordinates
     {
         public readonly int MapID;
-        public Vector2 Position;
+        public readonly Vector2 Position;
 
-        public float X
-        {
-            get => Position.X;
-            set => new ScreenCoordinates(value, Position.Y, MapID);
-        }
+        public float X => Position.X;
 
-        public float Y
-        {
-            get => Position.Y;
-            set => new ScreenCoordinates(Position.X, value, MapID);
-        }
+        public float Y => Position.Y;
 
         public ScreenCoordinates(Vector2 argPosition, int argMap)
         {