title: string concatenation with property binding in angular2
body: <p>in Angular 2 we have several way to create property bindings in templates.
  I could do something like this:</p>
  
  <pre><code>&lt;li *ngFor="#course of courses; #i = index" id="someselector-{{i}}"&gt;{{course}}&lt;/li&gt;
  </code></pre>
  
  <p>Is it possible to obtain the same result using the square brakets syntax?</p>
  
  <pre><code>&lt;li *ngFor="#course of courses; #i = index" [id]="someselector-i"&gt;{{course}}&lt;/li&gt;
                                              ^^^^^^^
                                    how create string concatenation?
  </code></pre>
  
  <p>Thanks,
  G.</p>