Make nice_menus module pass Coder Review

Automated project review reported several errors that we should be able to fix without too much trouble, since it's mostly coding standards errors (spaces missing, wrong indent, missing empty lines, etc...).

Let's try to bring back module's code in compliance with coding standards and fix all validation errors.

There shouldn't be any change of code, other than the ones recommended by the coding standards PAReview.

Additionally, I assume these changes could also be back-ported on other supported branches:
6.x-2.x PAReview report

Please let me know if you would have any questions, objections, comments, suggestions, recommendations or concerns on any aspects of this issue, I would be glad to provide more information or explain in more details.

Any questions, feedback, testing, changes, recommendations would be highly appreciated.
Thanks to all in advance.