title: swift: count recurring values in a dictionary
body: <p>I have a dictionary that is <code>[uid: true, uid: false, uid: false, uid: false]</code>. How do I, in Swift, count the number of <code>true</code> and <code>false</code> values so that I can see that there is 1 <code>true</code> and 3 <code>false</code> in this dictionary?</p>