Allow specifying viewDate as a prop, fixes #468

Suvish Varghese Thoovamalayil

2017-11-27 c276ecf7e6e9cc40656028f2ea69e1f2555d66c9

 test/testUtils.js

@@ -120,5 +120,9 @@

   getInputValue: (datetime) => {
      return datetime.find('.rdt > .form-control').getDOMNode().value;
   },

   getViewDateValue: (datetime) => {
      return datetime.find('.rdtSwitch').getDOMNode().innerHTML;
   }
};