Ref 71b2ac52: Disallow 2.x bypass of environmental helper methods
Fix #14180. Allow cross-frame use of focusin/out. Close gh-1369.
ajax: Fix #14207. file protocol returns status 0, see #8605.
Fix #14036. Remove user/pass from ajaxLocation. Close gh-1340.
Modify release script to create a headless tag for bower and publish to NPM
Update Sizzle: remove the use of version ranges
Use grunt and bower packages as local dependencies. Close gh-1433.
Update sizzle location in release script
Fixes #14535: update Sizzle to 1.10.13
Event: Fix #14544. Remove elem from event handle, close gh-1400.

This also reduces memory leaks if the element is removed without cleaning
events (e.g with native DOM operations).

Not pickable into the 1.x branch because oldIE still needs this.
Ajax: Fix #14424. Use ActiveX in IE9+ on local files, close gh-1434.

We can't feature detect ActiveX in IE11, but we can just call
it and catch whatever error occurs, then try normal XHR.
Ref #14180, let focusin/out work on non-element targets.
Release script: create tag after building CDN files
Keep bower_components in .gitignore.
Updating version to 2.1.0-beta2.
Updating the source version to 2.1.0-pre✓™
Release script: Add .npmignore and keep .gitignore when creating the tag
Release script: Add dist files in multiple commits for a clean final commit with a small diff
Ref #14503: Cherry-pick tests.
(cherry picked from commit 27b22f4ef5f3f291204f0e0f9f414ac503f6c8a8)
(cherry picked from commit 8dc0f2ea84e1861d8d8dfa7699268368c659f8e9)
(cherry picked from commit 936126f10de193e2bb1c8280dbc2361ca5d62e29)
Fixes #14548. Add main property to package.json