Added travis build status image.
Updated to test again major node releases.
Continuous Integration with Travis
Added 'Developers' section in README
Added Makefile. Pre-commit hook set on 'make test'
Code comments changes.
Updated package.json with 'docs' directory
Added documentation. We are using Docco.
Added AMD support. Fixes #2
Added more methods and corresponding test cases.
Added mocha.js test script.
CommonJS module export
Added _gu object. Added isInGUCRange().