PHP-Parallel-Lint shorttags option

[Dave13h]

Contribution Type: new feature Link to Intent to Implement: Link to Bug: https://github.com/Block8/PHPCI/issues/1339

This pull request affects the following areas:

• [ ] Front-End
• [ ] Builder
• [X] Build Plugins

In raising this pull request, I confirm the following (please check boxes):

• [X] I have read and understood the contributing guidelines?
• [X] I have checked that another pull request for this purpose does not exist.
• [ ] I have considered, and confirmed that this submission will be valuable to others.
• [ ] I have created or updated the relevant documentation for this change on the PHPCI Wiki.
• [ ] Do the PHPCI tests pass?

Detailed description of change:

Add the option to pass the short tags (-s) argument to PHP Parallel Lint so that files using PHP Short Tags can be linted.