Tests: Blacklist one effects test in Chrome 31

Chrome 31 reports incorrect offsetWidth on a table cell with fixed width.
This is fixed in Chrome 32 so let’s just skip the failing test in Chrome 31.
See https://code.google.com/p/chromium/issues/detail?id=290399
Support: Add expected support results for Safari 7 & IE11
Tests: fix Safari userAgent detection
Manipulation: Use textarea for missing IE defaultValue check

IE11 fixed the checkbox defaultValue issue but not textarea. Rather than
creating a new detect name I'm reusing the old one to protect anyone who
is unwisely using this externally. Re-fixing the defaultValue when it
doesn't need to be done is not a problem, so leave that code for IE11.

Fixes #14716
Closes gh-1495
Release: Instantiate a zip archiver, run archivers async
Updating the master version to 2.1.1pre.
Build: Upgrade npm devDependencies
Build: Remove obsolete UglifyJS workaround
Tests: Blacklist beforeunload test in iOS

iOS has the window.onbeforeunload field but doesn't support the beforeunload
handler making it impossible to feature-detect the support.

Fixes #14717
Closes gh-1496
Support: Add iOS6 support tests results
Build: Specify browserSets for TestSwarm directly
Ajax: Protect against exceptions thrown synchronously by xhr.send

When xhr.send throws an exception synchronously, the onerror handler may have
been called already which, unchecked, makes the exception bubble up outside of
jQuery.ajax.

We now catch the exception pre-emptively and only rethrow if we know it hasn't
already been notified through the onerror handler.

Fixes #14683
Core: Remove special case try/catch in isPlainObject

Fixes #14746
Build: Switch to explicit dependencies versions in bower.json
Attrs: Simplify an option hook

Since getter was removed in fdd78fad19ea3390cd96971cd29430e36378d137
there is no longer a need to wrap option element in order to get its value

Fixes #14756
Selector: update Sizzle
Build: Upgrade QUnit to 1.14.0
Docs: Change raises to throws in README test assertions
Support: Document box-sizing was unprefixed in Firefox 29