chore: update and cleanup dependencies
docs: add nodei.co badge to README.md
chore: exclude index.js from coverage report
chore: render coverage report only as html

```
--report <report-type>
     report type, one of html, lcov, lcovonly, none, defaults to lcov
     (= lcov.info + HTML)
```
chore: bump version to 0.1.7
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