Moving design decisions into the meta document
Updating HTTP message proposal based on feedback

- https://groups.google.com/forum/?fromgroups#!topic/php-fig/BjuMHOzTUJs
- Added link to RFC 2616
- Added getHeaderAsArray()
- Added more information about how URLs are absolute URLs
- Returning null if a stream size cannot be determined
- Specifying the protocol version format
Merge pull request #288 from mtdowling/http-message-updates

Http message updates based on feedback