Drop EL-5 support and introduce build-condition for optional tests
    
    - Drop EL-5 support
      - Drop BuildRoot: and Group: tags
      - Drop explicit buildroot cleaning in %install section
      - Drop explicit %clean section
      - Drop workaround for building with Test::More < 0.88
      - Spell checker is always hunspell now
    - Introduce build-condition for optional tests
      - Desired for modularity