Implement IsTrue / IsFalse checkers?

[frankban]

Is it worth introducing a c.Assert(v, qt.IsTrue) shortcut for c.Assert(v, qt.Equals, true)?
We always avoided shortcuts on the impression that usually the additional typing they save is not worth the price of having two different ways for expressing the same check.
On the other hand, IsTrue and IsFalse occur quite often in testing libraries and frameworks, and users expect they exist.