Add support for dynamic type ExpandoObject in spring.net expressions

In .NET framework 4.0 was added new type System.Dynamic.ExpandoObject this is an object whose member can be dynamically added and removed at run time, and now spring.net doesn't support evaluating expression on that object. This issue was described by me here http://stackoverflow.com/questions/10385572/expandoobject-with-spring-expression You can also find there instruction how to change code of spring.net to work with ExpandoObject.