Fix for null input value warning messages in react v15

package.json

@@ -1,6 +1,6 @@
 {
   "name": "synfrastructure",
-  "version": "6.0.1",
+  "version": "6.0.2",
   "description": "A collection of highly reusable React components paired with sass utilities and mixins for speedy UI development",
   "author": "Synapse Studios",
   "license": "MIT",

src/select.jsx

@@ -57,7 +57,7 @@ let Select = React.createClass({
         const selectedOption = this.props.options.findIndex(option => !! option.selected);
 
         if (selectedOption < 0) {
-            return null;
+            return '';
         }
 
         return this.props.options[selectedOption].value;