Updated readme to credit contributors

README

@@ -1,12 +1,17 @@
 ActionSheetPicker
 https://github.com/sickanimations/ActionSheetPicker
 
-Improvements more than welcome.
+Improvements more than welcome. Rather, they are kindly requested :)
+
+Thanks to sfilo and brettg for contributing to the project and making 
+ActionSheetPicker better for the iOS developer community.
 
 Created by Tim Cinel
 http://www.timcinel.com/
 
 Easily present an ActionSheet with a PickerView, allowing user to select from a number of immutible options.
 Based on the HTML drop-down alternative found in mobilesafari.
 
-Some code derived from marcio's post on Stack Overflow [ http://stackoverflow.com/questions/1262574/add-uipickerview-a-button-in-action-sheet-how ]  
+Some code derived from marcio's post on Stack Overflow 
+[ http://stackoverflow.com/questions/1262574/add-uipickerview-a-button-in-action-sheet-how ]  
+