title: Swift 3 conversion from Int to String
body: <p>In Swift 3, the <code>String</code> structure does not seem to have an initializer <code>init(_: Int)</code> that will allow the conversion from an <code>Int</code> to a <code>String</code>. My question is why does <code>let i = String(3)</code> work? What <code>String</code> method or initializer is it calling? Thanks.</p>