add first tests
fix misplaced callback
put walkdir results in list and sort

closes #6
add badges to readme
code style changes
add more tests

added devDependency 'lodash'
fix tests
fix tests (for real)

sorry, only tested on win, but linux handles things differently
clean before tests
simplify `npm test`
Merge pull request #12 from bwin/add-tests-new

Add tests (without performance hit)