Extract some helper methods

* HTML escaping
* logging
* option parsing
* author parsing
* message parsing
Make style more consistent and simplify a few things

* Object notation
* Fallback assignment logic
* Replace conditional with `or`
* Standardize style (quotes, spacing, concatenation, casing, etc)
* Return some values immediately instead of creating new variables
* Use CoffeeScript's object destructuring for require's
* Use CoffeeScript's exestential operator to check for functions
* Group similar methods together with comments
Add unit tests

* Export the Slack class for unit testing
* Install unit test dependencies (mocha + should)
* Set up "npm test" command
* Add Travis CI config
* Add `grunt watch` task to run tests on save
Merge pull request #11 from tinyspeck/unit-tests

Add unit tests