Merge branch 'release-0.1.7' into develop

* release-0.1.7:
  chore: bump version to 0.1.7
  chore: render coverage report only as html
  chore: exclude index.js from coverage report
  docs: add nodei.co badge to README.md
  chore: update and cleanup dependencies
chore grunt: fix cli args in grunt task
refactor: reduce responsibility of helper method
chore: drop support for node 0.8
Merge branch 'release-0.1.8'

* release-0.1.8:
  chore: drop support for node 0.8
  refactor: reduce responsibility of helper method
  chore grunt: fix cli args in grunt task