Manage bower dependencies with grunt-bowercopy

Tracked bower dependencies are located at "src/sizzle" and "test/libs".
The source-destination mapping is in the Gruntfile.

When updating a bower dependency, update the version in bower.json, run
`grunt bower`, and then commit the result. When adding a dependency,
update the bowercopy task accordingly.

Fixes #14615.
Closes gh-1452.
Revert "Ajax: Fix #14424. Use ActiveX in IE9+ on local files, close gh-1434."

This reverts commit 498e0e6c9bf486a0b1f16b455d65fcbc6c43867e.

We can't use the ActiveX XHR because it doesn't support events.
Reduce size by reordering variable declarations

Close gh-1421
CONTRIBUTING: Fixed link to style guide
Ajax: don’t test jQuery.ajax() on beforeunload in Chrome 31

Chrome 31 doesn't fire Ajax requests in beforeunload event handler.
There is no way for us to workaround it and it's been fixed in Chrome 32
so let's just blacklist Chrome 31 as long as it's in TestSwarm.
See https://code.google.com/p/chromium/issues/detail?id=321241
Build: Use absolute paths in .gitignore and .npmignore.

.gitignore/.npmignore treat all its paths as relative to *every*
directory in the repository. In most cases that’s not what’s desired.
Build: Upgrade to grunt-contrib-jshint 0.7.1 and squash subtasks

grunt-contrib-jshint 0.7.1 allows the jshintrc option to be set to true to have
it read the appropriate config file based on the file being checked. The only
place where we can’t use it is the check for dist/jquery.js that has the onevar
option removed.

Fixes #14504
Readme: Fix typo, thanks @tcort
Offset: Fix comment typo, thanks @AurelioDeRosa
Use the exact versions dependencies

And remove unused "which" package

Closes gh-1458
Build: Add the ability to remove global exposure.

Ref #14016
Build: add build option for setting the AMD name.

Fixes #14016.
Selector: update Sizzle

Fix #14584
Update AUTHORS.txt using git log --format="%aN <%aE>"
Remove hyphen from pre versions

- It is intentionally invalid semver as pre versions should never be released
- UI and Mobile already do this
Release script: jquery-release integration
Release script: minor formatting issue.
Gruntfile: fix watch task
exports/global: Do not attach global variables for most CommonJS environments

For CommonJS environments where the global already has a document, it is expected
that if a global is needed, the user can attach the global.

Fixes #14645.
Release script: _tracMilestone -> tracMilestone