Core: Change the sleep time in dont_return.php to a sane value

PHP sleep function accepts time in seconds, not milliseconds; the previous
value was starving the PHP FPM process pool.
Event: Don't test stopImmediatePropagation in Android 2.3

Android 2.3 doesn't support stopImmediatePropagation; jQuery fallbacks
to stopPropagation in such a case.
Event: Simplify the logic behind blacklisting Android 2.3 on one test
Core: Change the sleep time in dont_return.php from 100s to 30s

Half a minute is more than enough for the test to finish even in the slowest
browsers and in case of starving the PHP FPM process pool, one has to wait
for only half a minute to try again.
Package: Sort devDependencies
Build: Add commitplease for commit msg checking

Closes gh-1523
Tests: Remove obsolete speed directory

Closes gh-1551
Core: Fix comments for .get() method

Closes gh-1547
CSS: window.getDefaultComputedStyle may return null

Fixes #14736
Closes gh-1501
(cherry picked from commit 51910ba8a5aff4cd1a811f1fdb76a6c62a09a666)
Attributes: Trim whitespace from option text when returned as a value

Fixes #14858
Ref #14686
Closes gh-1531
(cherry picked from commit 9ec429cf6270e455aba4eba85f4db80e633806b6)

Conflicts:
	src/attributes/val.js
Manipulation: Change support test to be WWA-friendly

Setting the innerHTML property in an unsafe manner raises issues in
Windows Web Applications. Strings being passed into innerHTML cannot
include the name attribute.

Closes gh-1537
CSS: jQuery#hide should always save display value

Fixes #14750
Closes gh-1509
Effects: Don't overwrite display:none when .hide()ing hidden elements

Fixes #14848
Closes gh-1548
Event: Fix isDefaultPrevented for bubbled events in Android 2.3

Fixes #14897
Closes gh-1545
Selector: Use Element.matches in selector-native if available

Spec:
http://dom.spec.whatwg.org/#dom-element-matches

Support in Chromium:
https://code.google.com/p/chromium/issues/detail?id=326652

Fixes #14902
Closes gh-1524
Build: Update release script for new jquery-release API

Closes gh-1544
Support: Add Android support tests results
Build: change .gitattributes; use system line ends for non-JS files
Build: use browserSets from config file; allow to override
Build: set default testswarm timeout to 15 minutes

We're not testing on IE6-7 anymore.