Update to 1.19
    
    - New upstream release 1.19
      - Fixed a pasto in the "Support" section
      - Moved repository to https://github.com/theory/masonx-interp-withcallbacks/
      - Fixed installation documentation in the README so that it demonstrates
        using Build.PL rather than Makefile.PL, as the latter is not included in
        the distribution
    - Drop %defattr, redundant since rpm 4.4
    - Make %files list more explicit
    - Don't need to remove empty directories from the buildroot
    - Don't use macros for commands
    - Specify all dependencies
    - Run the test suite, except for tests requiring a web server