mmockito property update for real class

[ragavsathish]

When mocking the real class, current library does not allow to update the property of real class

classdef RealClass < handle
    %RealClass Class used in acceptance tests

    properties
        prop1
        prop2
    end
    ....

m = Mock(RealClass, 'tolerant');
m.prop1 = 5
Exception -  property not present.

This pull request has fix for above. Any comments, feedback is greatly appreciated.

Thanks,
Sathish