Version 0.19.0

    Considering family_url as part of the priority when selecting a URL to match.
    More explicit selection of C++ version.
    Ability to handle multiple parameters with the same name on the URL.
    Enable error_log to handle params to interpolate in the string.
    Reduced memory footprint of requests using of string_view.
    Configurable management of upload files that allows to load files on disk only, memory only or both disk and memory.
    Fixed error codes.
    Method not allowed now returns 'allows' header.
    Added method to access the gnutls_session struct.
    Code cleanups.
    Better use of RAII.
    Improved test coverage.