Update project URL.
    
    Also:
    - Eliminate unnecessary BRs and Rs.
    - Build with nauty support.
    - Add -format patch.
    - Force libtool to not defeat -Wl,--as-needed.
    - Be explicit about library versions as required by latest guidelines.
    - Filter out unnecessary Libs values from pkgconfig files.
    - Package doxygen tag file to enable cross-linking.