title: Webix UI - How to clear/reset/unset ui widget (input, select, date picker) value to empty?
body: <p>In Webix UI I have found a way to clear widget values based on form id collectively,  how do I clear widget values individually using some sort of mixin like <code>$$(&lt;form-id&gt;).clear();</code>.  </p>
  
  <p>Is there a proper way to reset values to default individually rather than collectively as I need control of individual elements?</p>
  
  <p>Please see existing fiddle for a sample set of elements.  There is an omitted select drop down element because I do not have the data set to populate the drop down,  as I normally populate it dynamically.</p>
  
  <p><a href="http://jsfiddle.net/02Lv1s9d" rel="nofollow noreferrer">http://jsfiddle.net/02Lv1s9d</a></p>