v0.4.1

# By Menno Pruijssers (2) and others
  fix unix timecode bug in handshake url. close #118.
  Instantiate errorInfo NSMutableDictionary using mutableCopy as suggested by Elshad. close #125.
  introduce closed flag to XHR transport. fix #130.
  Removed nill-checks
  Changed delegates from unsafe_unretained to weak
  Fix improper use of NSLocalizedDescriptionKey.
added changelog
Removed SBJson & JSONKit dependencies
fix url parameters encoding