title: In swift 3, how do you advance an index?
body: <p>I've trying to get a substring of a string starting from index 1 in iOS 10 beta 6, and its a headache as swifts strings are constantly changing and much documentation is out of date and useless.</p>
  
  <p>String has the substring(from:Index), but it can't accept an integer (which has been the case for a while), so I was planning to use startIndex and advance it by 1, but now Index has no advanceBy method, so I cannot do this:</p>
  
  <pre><code>let aString = "hello"
  let subString = aString.substring(from: aString.startIndex.advanceBy(1))
  </code></pre>
  
  <p>How can I get a substring from index 1? How can you advance an index these days,  and what is the point of the substring(from Index) method - how are you supposed to use it?</p>