package.json: use the right url for the github repo
LICENSE: update copyright year and break the lines
Update package.json.

* Add JSHint support
* Move test scripts there using npm run test
* Update dependencies
lib/enhance.js: Add license header.
Update Readme.md:

* Use Markdown syntax when possible
* Fix a typo
* Link to the license file
* Use "node.js" instead of "node"
* Add version and dependencies badge
style consistency changes
Fix JSHint warnings.
Update History.md:

* Link to the GitHub users
* Remove unneeded spaces before the unordered lists
* Use "node.js" instead of "node"
* Use code syntax when possible
* Fix typo