Update Module with Tests and 100% Test Coverage

[nelsonic]

Hi @dshaw,
As promised: #6 here's the Pull Request with the update to latest node.js (apologies for taking so long, we got "distracted" with our work... 😉 )

What's included in the PR?

• migrated tests from Tap to Tape so that we could collect code coverage info with Istanbul.
• added istanbul for code coverage (100%)
• sends code coverage stats to codeclimate.com (which also tracks code quality)
• incremented the version number to 1.0.0 to be Semver-compliant
• removed one line of unused/untested code from lib/env.js
• but, did not change any functionality in your module (so it should be 100% backward compatible)
• added pre-commit hook to check coverage so future contributions do not reduce test covreage
• added a couple more badges to the readme so that its clear to people that this module is maintained/loved! (the links are to our travis/codeclimate/dependencies we intend to keep the fork in our org for reference but the readme links can easily be changed with a find-and-replace if you like)

Please let us know if this is ok. otherwise let us know what you would prefer us to change.

Thanks!
N 🚀

[nelsonic]

We use fs.statSync because if the env.json file does not exist most apps probably wont work to the error (with full stack trace) is appropriate. what do you think?

[nelsonic]

@dshaw please let us know if anything is missing to get this PR merged.
I promise I won't be offended if you tell me to rip out chunks of it because I've gone too far or something...
We just really want to use your env module in our app(s) but can't until this update goes in ...
thanks!

[JoseCage]

Why this PR stills Open?? (not merged 🐛 🐛 )