Merge pull request #7 from tlvince/bug/conditional-versions

Check `file.versions` is set
Refactor the test
Add a property `versionMonitor` on req.files, a way to test the multi version file upload
Bump a new version
Remove useless function
User can add a 'nameGenerator' as parameter, to customize the stored file's name
Update attribute `req.files.file.name`, when the uploaded file gets stored with new name, refs #12
Bump new version 0.1.4
Update test
Inline test scripts, add test-watch
Modularise common mocha opts