v0.5.1

  Added method to pass cookies on conenct
  adjust cookie implementation
  add cookie example
  distinguish between handshake failed and unauthorized handshake
  add extra contributors file
  add examples for different event data types. ref #158
  clean up
add links to contributors profile
update changelog to v0.5.1
link contributors from readme
check HTTP status code of NSURLConnection responses during xhr polling transport just like when checking HTTP status code during handshake. Handles case when server restarts while connection with device is already established.
clean code
Merge commit '9e03bceb0df9e4ee20f787e3c01897b53b515e30' into develop