Css: Fix the "sanity check" test

The #dl element has 0 height so it's now considered hidden regardless
of its width.

(cherry-picked from 995f70777ac6c0f988a44807ef1399e73937b2ee)
CSS: Removed redundant "to the number" in comment

Ref 895ea6887dd02a44067d041db00c355c80e930a3
Core: Drop strundefined variable

Ref 29838b6cab6f2e508f3e9692f32918c72b1a504b
Closes gh-1628
CSS: Remove use of getDefaultComputedStyle

Remove optimization to make jQuery compatible with Google's Polymer project

Ref 274feb53cc9a99633dfac785d8b3b837d192c43c
CSS: Use pre-defined displays for html and body

Ref 60f546acb1c7136092b4fd01cccff052e468cc72
Ref 274feb53cc9a99633dfac785d8b3b837d192c43c
Ref a7724186c98734529b06bebb8f2dc7fc2b641011
CSS: Correct typo in the comment
Event: Restore the `constructor` property on jQuery.Event prototype

The original definition of the jQuery.Event prototype was paving over the
`constructor` property which was causing jQuery.isPlainObject to
improperly report that an instance of jQuery.Event was a plain object.

Fixes #15090
Closes gh-1580

(cherry picked from commit b807aedb7fee321fb3aa5d156a5a256ab0634e2d)
Manipulation: Update html5shiv elements

Include main, dialog, picture and template in html5shiv elements.

Fixes #15241
Closes gh-1655
README: Improve build instructions

Thanks @NickStefan

Ref 2e9c1ead76aaae8fde004e3cacde1e36c5fd2104
Ajax: remove event dependency from the ajax module

Ref 4e7f34f6296111f7f91d621397dfb02c6bf4c41f
Misc: Need for speed removed by 9ad6e7e
(cherry picked from commit ff928f5775566ee54f26fcb0f9a326719c32e63c)
Misc: Update all references to bugs.jquery.com

(cherry-picked from 3e89a53265bfdc992d7a97a01c5d1025e48e5906)

Fixes gh-1681
Closes gh-1716
Build: Upgrade to commitplease 2.0.0

commitplease now accepts "[tmp]:" and similar to temporary commits,
useful while updating pull requests that are squashed later.

(cherry picked from commit 5bc1ddc5cc96e509e0fadb0c1e3a70927de6ed1c)
Deprecated: Drop size and andSelf methods

(cherry-picked from f110360f65a268e959ae892ca36e85da3d91e606)

Fixes gh-1749
Closes gh-1822
Test: Switch leftover andSelf to addBack
Change broken url to wayback one
README: Update the description of the deprecated module

(cherry-picked from 1d752731011d35e985271334ff98186728949f03)

.andSelf is now gone.
Ajax: Fix for request aborted in ajaxSend

Fixes gh-1775
Close gh-1619