The log member is changed to derive from std::ostream. A new
class dstream is derived from std::ostream to support redirection
to the Visual Studio Output Window if a debugger is attached.
Obsolete classes abstract_ostream and its derived variants are
removed.
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
