plain skin: menu style improvements.
plain skin: headers style fix.
pb::detail::convert() bug fix.
protobuf_error, protobuf_parsing_error and protobuf_serialization_error declaration.
web::repository::send_protobuf() integration with protobuf_serialization_error.
web::repository::send_file() bug fix.
web::repository::send_file(): Content-Length support.
Integration with bacs::problem::info update.

pb::problem::Info declaration.
pb::convert() update.
repository: read_info_() and write_info_() update.
info view of plain skin update.