added Vector.useList and Vector.copy, changed Vector.fromList

Author: Raymond Hulha

lib/src/vector.dart

@@ -3,17 +3,23 @@ part of chronos_gl;
 class Vector {
 
   Float32List array = new Float32List(3);
-  
-  
+
   double get x => array[0];
   double get y => array[1];
   double get z => array[2];
-  
+
   set x(double v)  => array[0] = v;
   set y(double v)  => array[1] = v;
   set z(double v)  => array[2] = v;
 
-  Vector.fromList( this.array);
+  // Careful, this shares the data...
+  Vector.useList( this.array);
+
+  Vector.fromList( Float32List array) {
+    this.array[0] = array[0];
+    this.array[1] = array[1];
+    this.array[2] = array[2];
+  }
 
   Vector( [double x=0.0, double y=0.0, double z=0.0])
   {
@@ -38,6 +44,10 @@ class Vector {
       return this;
   }
 
+  Vector copy() {
+    return new Vector.fromList(this.array);
+  }
+  
   Vector add( Vector v) {
       array[0] += v[0];
       array[1] += v[1];