Huge Update - One Class, Simple Code, New Graphics, Animations, Bug Fixes, Performance Improvements

Version 4.0
- Code reorganized, cleaned-up, and condensed. DropboxBrowser is now one easy-to-use class (previously three classes with complex delegate calls)

- New icon, graphics, and help menu for example project  
- Simplified Navigation Controller customization. Please refer to the new setup and integration procedures

- Added Icons for over 100 types of files and folders supported by Dropbox - proper icon is shown next to each file

- Added four new delegate methods and depreciated older methods

- New TableView animations - changes in directories are now animated  
- New Navigation Bar - new design, also shows title of current folder  

- Updated Refresh Control - now the refresh control actually fetches updates from Dropbox and displays them  
- Removed Loading HUD for iOS 6+ users - the refresh control now appears instead of the black overlay. If you support versions lower than iOS 6, the HUD will be used.

- Fixed Done Button Bug where it may randomly disappear or reappear  
- Fixed Back Button issue where the user could back up past the Root Directory  
- Fixed TableView Subtitle information. Formatting now mimics the Dropbox App  
- Fixed Download Progress View issue where the download progress would not reset after each download  
- Major Performance Improvements 

- Added open-source license (MIT license). Don't worry - It's the same license you added to the top of each class in your last commit.

![screenshot](https://f.cloud.github.com/assets/2374407/521068/0d5c5ccc-bf65-11e2-93d5-6368f68e1638.png)