net_stats.cpp

    - client: when autoproxy detection is in progress don't attempt to use
        old values
    - client: user defined proxies should take presidence over automatically
        detected ones.
    - lib: Re-implement the assignment operator for proxy_info, http_curl.cpp
        uses it to clone the proxy information for each http op.  See set_proxy();

    client/
        client_state.cpp
        http_curl.cpp
        net_stats.cpp
    lib/
        proxy_info.cpp, .h

svn path=/trunk/boinc/; revision=18971