Merge pull request #1905 from blacktemplar/option_undefined_this_fix

binds handleTouchEnd in Option component

src/Option.js

@@ -11,6 +11,7 @@ class Option extends React.Component {
 		this.handleMouseEnter = this.handleMouseEnter.bind(this);
 		this.handleMouseMove = this.handleMouseMove.bind(this);
 		this.handleTouchStart = this.handleTouchStart.bind(this);
+		this.handleTouchEnd = this.handleTouchEnd.bind(this);
 		this.onFocus = this.onFocus.bind(this);
 	}