Bump to 2.3.1

Author: iwb-kevin-hirsch

DropDown.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name = "DropDown"
-  s.version = "2.3.0"
+  s.version = "2.3.1"
   s.summary = "A Material Design drop down"
 
   s.description = <<-DESC

README.md

@@ -2,7 +2,7 @@
 
 [![Twitter: @kevinh6113](http://img.shields.io/badge/contact-%40kevinh6113-70a1fb.svg?style=flat)](https://twitter.com/kevinh6113)
 [![License: MIT](http://img.shields.io/badge/license-MIT-70a1fb.svg?style=flat)](https://github.com/AssistoLab/DropDown/blob/master/README.md)
-[![Version](http://img.shields.io/badge/version-2.3.0-green.svg?style=flat)](https://github.com/AssistoLab/DropDown)
+[![Version](http://img.shields.io/badge/version-2.3.1-green.svg?style=flat)](https://github.com/AssistoLab/DropDown)
 [![Cocoapods](http://img.shields.io/badge/Cocoapods-available-green.svg?style=flat)](http://cocoadocs.org/docsets/DropDown/)
 [![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)