Update jQuery to v2.2.2.

remove empty sass if directives

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Add Android to Sauce testing
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Remove the now unused glob devDependency

Use "latest" version specifier (when applicable) in Sauce tests

Refs http://sauceio.com/index.php/2016/03/new-browser-version-shortcuts/
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Add Wall of Browser Bugs entry for #17338
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https://crbug.com/595210

Closes #17338
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Fixes #19114
Closes #19482, #19299

Add jQuery and Tether to npm dependencies

Mention https://webkit.org/b/153856 in the docs

Refs #14839, #19088
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Remove iOS virtual keyboard bug section from docs

Closes #19532
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CONTRIBUTING.md: Prohibit "+1" comments in favor of reactions
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Jekyll 3.x has it as a dependency already.

Make hound fail on violations

Refs https://github.com/blog/2119-add-reactions-to-pull-requests-issues-and-comments
Refs https://github.com/dear-github/dear-github/issues/141#issuecomment-195106918
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Wall of Browser Bugs: Stop mentioning IE11

Sounds like IE11 isn't getting non-critical fixes anymore, so there's no point in mentioning it (just like there's no point in mentioning IE10).
Help us, Edge-Wan Kenobi! You're our only hope.
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http://bugzil.la/1139853 was resolved as a duplicate of http://bugzil.la/924068
Refs #15990
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Add native title tooltip IE11/Edge bug to wall of browser bugs

Travis CI: Remove now-unused $GEMDIR env var

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Remove the now unused btoa dependency.

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Also switch to `^`.