Basic HTTP message proposal
Remove the link between requests and responses
Use @return self
Improve callable and setBody() definition
Return type fix
Simplify body types
Removing mutators from ResponseInterface
Removing custom exceptions as they add no value over SPL exceptions
Removing addHeaders() from MessageInterface
Merge branch 'remove-addHeaders' into modified-http
Merge branch 'remove-custom-exceptions' into modified-http
Starting to refactor the proposal
Updating headers
Adding streams
Tuning some descriptions and adding a MessageFactoryInterface
Must specify statusCode when creating reponses
Adding more information about multi-valued headers and how headers are case-insensitive
Adding more motiviation information
Text cleanup
Fixing typo