Setup linter with Airbnb JavaScript style guide

[arreche]

Run it with: npm run lint

[rhgksrua]

When eslint detects any errors, it will exit with non zero status. Right now, if there is an error with eslint, npm will also error. Si it looks like eslint isn't working correctly. Running eslint public test || true or npm run lint --silent will hide npm errors.

I actually don't care if npm shows its own errors, but others might get confused.

Also, if any one is running npm version 3 or greater, it doesn't install peer dependencies automatically. So npm run lint will break.

[rhgksrua]

Right now it looks like the current airbnb config is for ES6. You might have to switch to eslint-config-airbnb-base package and use airbnb-base/legacy in eslint.js to lint ES5. Also, adding another package to suppress jasmine errors would nice (errors for describe and expect).

[rhgksrua]

I have some things I realized while I was running the linter.

• Jasmine plugin is applied globally. What we can do is create another .eslintrc.js with jasmine plugin in the test/ directory and remove jamine plugin from .eslintrc.js in root directory. This way, jasmine plugin only applies in the test/ directory. You can read more about this in Configuration Cascading and Hierarchy
• Jasmine throws error for undefined functions for test files (index_spec.js). We might have to turn off no-undef rule in the test/ directory. You can use the config file or inline comment for this.

[rhgksrua]

Everything looks good. You should merge it once another person takes a look.