sparse list of values using ranges : <p>is there a more terse way of writing</p>

<pre><code>listOf('a'..'z','A'..'Z').flatMap { it }
</code></pre>

<p>The idea here is to iterate over some values in a range, like the numbers from 1 through 100, skipping 21 through 24</p>

<pre><code>listOf(1..20, 25..100).flatMap { it }
</code></pre>
