title: uib-datepicker-popup calendar with null/NaN if input initially null
body: <p>I use UI Bootstrap 1.3.2, Bootstrap 3.3.6 and Angularjs 1.5.5, but I'm having a problem with uib-datepicker-popup. If the value of the corresponding input field is null/not set, the calendar shows undefined date fields (null, NaN):</p>
  
  <p><a href="https://i.stack.imgur.com/LBdi1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LBdi1.png" alt="enter image description here"></a></p>
  
  <p>Code of input field:</p>
  
  <pre><code>&lt;input type="text" uib-datepicker-popup="dd.MM.yyyy" datepicker-options="datepickerOptions" ng-model="mydto.teilnahmebis" /&gt;
  </code></pre>
  
  <p>The initDate option is ignored - code from controller:</p>
  
  <pre><code>$scope.datepickerOptions = {
                      minDate : new Date( '2010-01-01' ),
                      initDate : new Date() 
                  };
  </code></pre>
  
  <p>The popup works if the input field already has a value. But normally that's not the case. Any idea, how to resolve this issue? Thanks for an answer.</p>