Code improvements and error fixes

- Code has been actually linted
- Directory `node_modules` has been added to `.gitignore` instead of keeping the whole `node_modules` directory
- All tested passed with default `grunt` task
- The variable `grunt.config.data.aws.data` redefinition has been removed, because there is no variable like:

```JavaScript
var response = grunt.config.data.aws.data = {};
```