added ConstructPointerObject function which returns a UVaRestJsonObject

We're finding that pointers that are created using the ConstructPointer method are causing errors when trying to save them in pointer fields in Parse. The typical error we get back says that it expected a pointer but received a string. This makes sense since the ConstructPointer method returns a string.

It seems to work better if you pass an object to pointer fields, so I've added a method called ConstructPointerObject that does the equivalent of ConstructPointer but returns an object instead of a string. I'm interested to know what the use case for the version of ConstructPointer that returns a string.