This line is a ugly trick and I fix it now.

There is a problem.
For example, 

`(1).should.have.property('constructor', String)`

`String` here is a function, and if String be blockify, this test would pass. So I should know whether the expect value is to test equality or test blockify.

Now the code implement is that: if property value and expect value are both function, then give up blockify, test equality directly.