Bump the dependency on js-yaml.

        It contains some bug fixes that may be of interest.

        `npm install --save-dev` also happened to reformat the package.json file.
Tell Travis to upgrade npm before doing anything else.

        This should solve the issue with "No compatible version found".

        Thanks for Loren West for pointing me in the right direction.
Adding Changelog entry.

        Mostly to see if makes the "before_script" addition to .travis.yml in the last commit to start working.
Trying before_install instead of before_script to fix package.json version parsing issue.
Merge pull request #158 from markstos/bump-js-yaml-dependency

Bump the dependency on js-yaml.