title: datetime format bug for jquery.inputmask 3.3.4?
body: <p>when I upgrade my <code>jquery.inputmask</code> plugin from 3.3.1 to 3.3.4, I noticed that datetime format for mask is changed.</p>
  
  <pre><code>// in version 3.3.1
  $("#textbox").inputmask("y-m-d");
  $("#textbox").inputmask("h:s");
  
  // in version 3.3.4
  $("#textbox").inputmask("yyyy-mm-dd");
  $("#textbox").inputmask("hh:mm");
  </code></pre>
  
  <p>In v3.3.4, letter "m" is used for both "month" and "minute", some mask definitions are likely to cause conficts, for example</p>
  
  <pre><code>$("#textbox").inputmask("yyyy-mm-dd hh:mm"); // ERROR! can't input anything into textbox 
  $("#textbox").inputmask("mm/dd/yyyy hh:mm xm"); // but this works fine
  </code></pre>
  
  <p>This problem only happens in <code>jquery.inputmask 3.3.4</code></p>
  
  <p>Is it a bug? How can I make the mask <code>"year-month-day hour:minute"</code> work in my page ?</p>