No longer require unsafe option

- Change unsafe/fixed to use IntPtr or MarshallAs instead.
- Added methods in physac to marshall IntPtr returns to PhysicsBodyData.

Bindings/Program.cs

@@ -1,11 +0,0 @@
-
-namespace Bindings
-{
-    static class Program
-    {
-        static void Main(string[] args)
-        {
-            Examples.core_basic_window();
-        }
-    }
-}