c# reflection gettype, getnestedtypes, getproperty

reference:
http://www.java2s.com/Tutorials/CSharp/System/Type/C_Type_GetNestedTypes_.htm
https://stackoverflow.com/questions/5566428/is-there-a-way-to-get-a-list-of-innerclasses-in-c
https://stackoverflow.com/questions/2535287/getting-nested-object-property-value-using-reflection
https://msdn.microsoft.com/en-us/library/kz0a8sxy(v=vs.110).aspx
https://stackoverflow.com/questions/1196991/get-property-value-from-string-using-reflection-in-c-sharp
https://msdn.microsoft.com/en-us/library/6hy0h0z1(v=vs.110).aspx