`count()` is too imperative. use `length()` instead 

See https://github.com/mathiasverraes/lambdalicious/issues/11

Why use `count()` when you have `length()`? Imperative vs. Declarative.
Also, length gives us the added bonus that it's only defined in terms
of itself and other λlicious functions.

double win?
![cheers](http://replygif.net/i/1341.gif)
or use existing ones? `$this->assertEquals(2, length([a, b]));`