0.8.0

• New image comparison algorithm is implemented:
  • gm compare replaced with custom diff. For now, GraphicsMagick
    is still required for other image manipulations.
  • tolerance setting is removed in favor of "strict mode": by default,
    only noticable changes (according to ciede2000 metric) will be treated
    as failure, to treat all changes that way user can enable
    strictComparison option.
  • in case if some element in focus during test can potentially have
    blinking caret displayed, diff will try to ignore caret.
• Remove built-in TeamCity reporter. If you really want
  it, you can adapt 0.7.x reporter to the current version
  of gemini and publish it in separate package.
• Remove legacy ability to specify browsers as array which
  was deprecated since 0.4.0.
• Add experimental programmatic API.
• Add --grep option to gather and test commands, which
  allows to execute only suites, matching the pattern (@scf2k).
• Show required dimensions in error message when origin does
  not fir to full-page screenshot (@scf2k)