The verb interfaces now use verb::unknown instead of
boost::optional<verb> == boost::none to indicate that
the request-method is an unrecognized string.
The http::header interface is modified to focus more on the
verb enum rather than the string. For recognized verbs, the
implementation stores an integer instead of the string.
Unknown verbs are still stored as strings.
* header::method now returns a verb
* header::method_string returns the method text
The version field is moved into message_v1, all public interfaces
are reworked to identify HTTP/1 wire format operations (suffix "_v1")
versus general HTTP.
* Fix warnings
* Port cmake scripts to linux
* Add command line options for running test suites
* Add examples to CMakeLists
* Return std::uint64_t from writer::content_length
* basic_parser::write takes asio::const_buffer instead of pointer and size
* Turn message test back on now that it passes
* Rename to http::headers, use std::allocator, remove http_headers
* http::message::method is now a string
* Refactor to_string for ConstBufferSequence
* Remove chunk_encode from the public interface
* Initialize members for default constructed iterators
* Disallow default construction for dependent buffer sequences
Refactor http::message serialization:
* Serialization no longer creates a copy of the
headers and modifies them
* New function prepare(), sets Connection, Transfer-Encoding,
Content-Length based on the body attributes and caller options.
Callers can use prepare() to have the fields set automatically,
or they can set the fields manually.
* Use write for operator<<
* Tests for serialization
