Add wrappers for mockStatic, mockConstruction

[jselbo]

This adds nice reified functions for Mockito.mockStatic and Mockito.mockConstruction. This also adds a whenever wrapper for MockedStatic stubbing.

Before:

mockStatic(A::class.java).use { mock ->
  mock.`when`<String> { A.method() }.thenReturn("hi")
}

After:

mockStatic<A>().use { mock ->
  mock.whenever { A.method() } .thenReturn("hi")
}

In the future I'd like to add some documentation with caveats around "static" method stubbing of Kotlin code.

Thank you for submitting a pull request! But first:

• Can you back your code up with tests?

[TimvdLippe]

Nice thanks!