Defer IO.copy_stream

Otherwise these calls will block Reel's reactor
Dup original headers before modifying (fixes #81 and #85)
Bump version to 0.4.0.pre5
EventStream example
Update ServerSentEvents.rb
Added EventStream example
Update and rename ServerSentEvents.rb to server_sent_events.rb
Update server_sent_events.rb
Update server_sent_events.rb
Merge pull request #86 from Asmod4n/master

Added EventStream example
Move framework adapter info above Ruby API info in README