NumericRange[Double].contains() doesn't work due to rounding errors

`NumericRange` is internally implemented by means of arithmetics - causing some trouble when working with doubles:

```scala
val r = 0.0 to 1.0 by 0.1
r.indexOf(r(3))  // => 3
r.contains(r(3)) // => false
```

Problem is that numeric range is a collection - really bad things can happen if someone passes NumericRange where Seq is expected and `contains()` method is used.
