Follow up patch release for bug fixes and documentation improvements.

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CSS

Forms

• #14234: Drop the IE specific hacks for temporal inputs and replace with a Safari media query hack to avoid the IE problems altogether.

Button groups

• #15086: Don't remove focus outline from buttons in button groups.

Badges

• #14915: Properly color badges in .active item of <ul>-based list groups.
• #15052: Fix active styles when in non-anchor .list-group-item.

Jumbotron

• #14979: Override .jumbotron padding within .container-fluid to match .container.

Navbar

• #14965: Reset border-radius on top corners on dropdown menus in fixed bottom navbars.

Popovers and tooltips

• #14936, #15019: Fix some bugs in and deprecate diagonal placement classes for tooltips.
• #15046: Add full font overrides for popovers and tooltips.

Theme

• #14381: Correctly override active dropdown items in collapsed navbars in the theme.
• #15018: Correctly override active dropdown items in collapsed navbars.

JS

• #14925: Make button plugin's focus shim recognize focusin event in addition to focus event.
• #14931: Add workaround for seemingly spurious tooltip viewport unit test failures on iOS 8.
• #14927: Fix modal backdrop overlaying the modal's scrollbar.
• #14933: Center modal at all times.
• #14993: Have Carousel ignore keyboard events emited by <input>s or <textarea>s.
• #15088: Dropdown: Ignore keydown events coming from inputs and textareas.

Docs

Browser bugs

• #14920: Add Wall of Browser Bugs entry for #14868.
• #14922: Add Wall of Browser Bugs entry for #14708.
• #14958: Add Wall of Browser Bugs entry for #14409.
• #14985: Add Wall of Browser Bugs entry for #14972.

Accessibility

• #14951: Assorted accessibility (and some consistency) fixes.
• #15009, #15085: Glyphicon accessibility improvements.
• #15087: Wash-up of some stray dropdown examples' ARIA roles.

Contributing guidelines

• #14949: Explain issue bots & PR bots in CONTRIBUTING.md.
• #14959: Mention common contributor mistakes in CONTRIBUTING.md.

Components, examples, etc

• #14917: Use HTML5 <footer> tag in examples.
• #14945: Replace deprecated uses of .pull-left & .pull-right in .media docs.
• #14986: Mention Safari font size issues with fixed-width .containers in Printing docs.
• #14989: Add event.relatedTarget + data-* example of how to vary modal content based on which button activated the modal.
• #15015: Add initialization examples to tooltip and popover "Opt-in functionality" callouts.
• #15077: Document required .active class on one carousel slide.

Customizer

• #14954: Fix config.json file upload widget event listener.
• #14980: Integrate Autoprefixer into the Customizer.
• #15031: Remove file type check from config import.

Build tools / Packaging

• #15072: HTML validation: X-UA-Compatible now validates, so remove it from the list of ignored errors.
• Update devDependencies