Library mainainance

- Replace Mocha and Chai with Jest for testing the library.
- Replace codecov with coveralls for tests coverage.
- Update devDependencies.

fix typo in link

Merge pull request #9 from georapbox/issue-#8

Close issue #8

Merge pull request #9 from georapbox/issue-#8

Close issue #8

update devDependencies

[ci skip] fix typo

update docs

[ci skip] library build

v1.0.1 builds