0.9.0

• Replace GraphicsMagick with lightweight png-img library (@j0tunn).
  As for this version, gemini no longer requires any external tool for
  image processing.

• CSS coverage now supports source maps (@scf2k).
  If your CSS has the sourcemap, coverage report will show original files.

  You can use sourceRoot option to tell gemini where are your sources
  located on a filesystem.

• CSS coverages statistics will now also be written to coverage.json
  file (@scf2k).

• Add coverageExclude option to allow exclude certain files from coverage
  report (@scf2k).

• Add index page to coverage report and improve appearance of a the coverage
  pages (@scf2k).

• Restructure documentation and add quick start guide in russian and english
  (@jk708).