Add -h option as well as --help
Merge remote-tracking branch 'origin/master'
Fixes #26 - Allow update single module: david update [module ...]
Version 2.3.0 notes
2.3.0
Add node.js 0.11 in travis.
Sort by name.
Update package.json.

Add bugs and author properties and reorganize properties.
Trim trailing spaces.
package.json: Specify the files to install when installing via npm.
Update .gitignore.
Add JSHint support via `npm run lint`.

Also remove unneeded parentheses.
Update README.md.
Rename variable for consistency.
Add jshint check in npm test command.