[WIP] Rework grunt tasks

This pull-request will rework the grunt tasks and prepare the repository for the new release process. 

Todo's:
- [x] Update dependencies to higher version
- [ ] Rework current grunt tasks
- [ ] Create tasks for new release process to dist folder and dist.zip
- [x] Clean javascript/css against the jshint, jscs, css lint rules
- [x] Add version to banner of dist files
- [ ] Integrate version property in datepicker object
- [ ] Add grunt task to update version in datepicker object
This would be cleaner using Array#join:

```
    banner: [
        '/*!',
        ' * Datepicker for Bootstrap v<%= pkg.version %> (<%= pkg.homepage %>)',
        ' *',
        ' * Copyright 2012 Stefan Petre',
        ' * Improvements by Andrew Rowls',
        ' * Licensed under the Apache License v2.0 (<http://www.apache.org/licenses/LICENSE-2.0>)',
        ' */'
    ].join('\n'),
```

Also, either you're missing a "<" in the license link, or you have an extra ">" at the end of it.