Update README.md

Fixed spelling and added missing commas for DK.
Adds unit test for processor chaining. Adds try/catch in error handler because next version of Dart SDK will throw error when trying to modify the status code after the header has been sent: http://code.google.com/p/dart/issues/detail?id=14505
Merge branch 'master' from upstream into improvements
Removes utf package in favour of using build-in dart:convert. Adapts logging to log4dart. Fixes log4dart version.
Merge pull request #5 from srmelody/master

Update README.md
Merge pull request #6 from fkleon/improvements

Various minor improvements
Update README.md