title: Check if one string is a prefix of another
body: <p>I have two strings which I'd like to compare: <code>String</code> and <code>String:</code>. Is there a library function that would return true when passed these two strings, but false for say <code>String</code> and <code>OtherString</code>?</p>
  
  <p>To be precise, I want to know whether one string is a prefix of another.</p>