Array.cs - first attempt to get the "for each' correctly working with Array when dynamic properties have been set.

This code:
  	var a:Array = [];
        	a[0] = 10;
        	a[1] = 11;
        	a[2] = 12;
        	a["key_a0"] = "a0";
        	a["key_a1"] = "a1";
        	a["key_a2"] = "a2";
        	for each(var o:Object in a)
        	{
        		trace(o);
        	}
        	for (var o:Object in a)
        	{
        		trace(o);
        	}

Will now produce:
10
11
12
a0
a1
a2
0
1
2
key_a0
key_a1
key_a2