fix bug with radio and checkbox validation

This was introduced with #5738.

The statement was in the wrong line. This fixes a bug where the validation of radios and checkboxes was not recognized in the final validation result.

Now it works great :)
Tabs heavy-handed tabindex setting fix

This change is to remove the tabindex attrs instead of setting them to zero on change of tab.

The problem with having a zero tabindex (on a div for example) is that Chrome highlights the area on click and includes it in the tabbable items, so removing the tabindex is a better option as it reverts the tab section to its default tab behaviour.
Refining tabindex setting on tab change

All first-children of tab-content was having a tabindex assigned on the change of tab. This caused the unnecessary inclusion of non-form items in the tab ordering and wasn't required to make the tab content accessible. This change is to leave all tabindex attrs of the tab-content items alone, but leave the setting of the tabs themselves unaffected.
Merge branch 'master' of https://github.com/jopotts/foundation into jopotts-master
Keyboard navigation on tabs no longer freezes the page, fixes #5882
Merge branch 'jopotts-master'
Merge pull request #5782 from christianseel/patch-7

fix bug with radio and checkbox validation
5.4.6 release
Merge branch 'master' of github.com:zurb/foundation
Updating Docs changelog
Fixing links on latest changelog
Change lingering uses of 'offcanvas' and 'off canvas' to 'off-canvas', fixes #5664
Fix incorrect pseudo element in use in dropdown buttons, fixes #5832
Disable outlines and selection highlight on switches, fixes #5897
Merge branch 'master' of https://github.com/zurb/foundation
Fix vertical button groups not stacking when a radius or round class is added, fixes #5909
Fix Clearing docs having incorrectly-named JS events, fixes #5179
Allow accordion content panes to be defined in JS with a custom class, #5912
Remove glow on dropdowns and their buttons when focused, fixes #5757
Fix example

Add missing `columns` class.