add warning about WebKit bug to the justified nav example itself
add release checklist to CONTRIBUTING file; fixes #11290
Merge pull request #11409 from twbs/add-release-checklist

add release checklist to CONTRIBUTING file
Add unit test for #9920

Merges #10385
Don't deselect radio buttons in data-toggle; fixes #9920

Merges #10787
<3 @asselin for figuring out this combo of 2 patches for #9920; re-grunt
Merge pull request #11376 from twbs/double-click-radio-fix

Double-clicking on a .btn-ized radio button shouldn't de-select it
Merge pull request #11385 from twbs/justified-nav-example-warning

add warning about WebKit bug to the justified nav example itself
Merge branch 'master' of https://github.com/twbs/bootstrap