Feature/accessor inheritance

[kavics]

Issue-1

To access a non-public field of an abstract class needs a new constructor on the ObjectAccessor that allows differentiation of the object instance and its type. For example, access to the "_data" field of the Node needs the following lines:

var accessor = new ObjectAccessor(testNode, typeof(Node));
accessor .SetField("_data", testValue);

Issue-2

To access a static member of the inheritance chain, the BindingFlags.FlattenHirerchy flag need be used in reflection calls.