Toggle: add toggle state persistence

The "persist" data option allows a toggle element to
remember it's on/off state using localStorage or
sessionStorage.
Toggle: add persist docs and example
Test: add toggle persist unit tests
Documentation: Pointed contributor guideline and version history links to the new HTML versions
Merge pull request #4244 from pjackson28/pointtoversionhistory

Documentation: Pointed contributor guidline and version history links to the new HTML versions
Merge pull request #4237 from patheard/persist-toggle

Toggle: add toggle state persistence
[CSS] Disable pull-right/left on grid-specific columns when the current breakpoint doesn't match.
[Build] Modified CSSLint options to allow regex selectors.
Merge pull request #4206 from thomasgohard/fix-pull

[CSS] Disable pull-right/left on grid-specific columns when the current breakpoint doesn't match
Removed unused hard-coded test code
Removed unused test folder
Documentation: Updated the downloads and versioning links
Merge pull request #4251 from pjackson28/updatedwnldversioninglinks

Documentation: Updated the downloads and versioning links
Merge pull request #4248 from LaurentGoderre/removed-hardcoded-tests

Removed unused hard-coded test code