Replaced occurrences of '++' with '+= 1'.
Merge pull request #3685 from thomasgohard/js-performance-improvements

Replaced occurrences of '++' with '+= 1'
Tables: Removed role='grid' from DataTable wrapper
Merge pull request #3701 from pjackson28/removerolegridtables

Tables: Removed role='grid' from DataTable wrapper
Auto-generate overlay close button.
Minor changes to the overlay header and close button CSS to handle overlays without titles.
Updated English working examples and added French working examples.
Merge pull request #3700 from thomasgohard/plugin-overlay

Improvements to overlay plugin