title: ng-pattern not working with regular expression
body: <p>My form has below inline validation</p>
  
  <pre><code>&lt;form name="coForm" novalidate&gt; 
  &lt;div&gt;
     &lt;label&gt;Transaction: &lt;/label&gt;
     &lt;input  type="text" name="transaction" class="form-control"
             placeholder="&lt;Direction&gt; &lt;Message Type&gt;, ex.:OUT X12214" 
             ng-model="newco.transaction" 
             ng-pattern=/(^(IN )([A-Za-z0-9 &amp;_]+))|(^(OUT )([A-Za-z0-9 &amp;_]+))/ 
      required&gt;
  
        &lt;span style="color:red" 
           ng-show="coForm.transaction.$dirty || 
                    coForm.transaction.$invalid"&gt;
        &lt;span ng-show="coForm.transaction.$error.pattern"&gt;
            Enter correct value for Transaction
        &lt;/span&gt;
        &lt;span ng-show="coForm.transaction.$error.required"&gt;
              Transaction is required.
        &lt;/span&gt;
  &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>But the validation works only for <code>required</code> and not for <code>pattern</code></p>
  
  <p><a href="http://jsfiddle.net/DivB/pwan5L0g/" rel="nofollow">Here is the fiddle</a></p>
  
  <p>Below are the few examples for positive match:</p>
  
  <pre><code>OUT X12214
  In X12850
  IN ARRANT
  OUT CORREC&amp;TRANSLEG
  OUT TEST_TEST
  IN TEST2&amp;TEST2
  </code></pre>