Support NewDelegate expressions

[GoogleCodeExporter]

e.g., currently falls back on ToString:

> source <@ (System.Func<int,int>(fun i -> i + 1)) @>;;
val it : string =
  "NewDelegate (System.Func`2[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]],
             i,
             Call (None, Int32 op_Addition[Int32,Int32,Int32](Int32, Int32),
                   [i, Value (1)]))"

Original issue reported on code.google.com by stephen....@gmail.com on 27 Feb 2011 at 5:06