fix#114, fix#117, fix#136
* Added init() to Reader requirements
* Reader must be nothrow constructible
* Reader is now constructed right before reading the body
- The message passed on construction is filled in
Conform to the Networking TS by renaming the Streambuf concept
to DynamicBuffer in all places. Values of types meeting the
requirements of DynamicBuffer are renamed to dynabuf.
See:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4478.html#requirements.dynamic_buffers
* Headers renamed
* Formal parameter names renamed
* Template argument types renamed
* Documentation updated