Fix IE10 bug when cloning an object element without a parentNode
Manual merge after fetch upstream
Fix weird clone bug and add a unit test to verify
Updated the comment above the fix
Add support check, added assertion to check if cleared, add edge case for backgroundPosition
Remove test file that I didn't mean to get into the previous commit
Sizzle: tagged versions are now in the repo; update selector engine list
Sizzle: fix  selector in Chrome 21. Fixes #12492.
Chrome fails in ajax.js tests because TestSwarm/Ngnix won't give HEAD requests any respect. Skip them rather than hear Swarmy call FAILURE on each run.
deferred.promise(obj) should work with non-objects. Fixes #12521. Much needed unit tests added!
Fix #12534. Don't die on browsers lacking getBoundingClientRect.
Fix #12536. Start at .offset() 0,0 if no getBoundingClientRect.

This lets us still add the other offset components to the number so they're less wrong. Affects BlackBerry 5 and iOS 3, everyone else has gBCR.
Fix #12447: Ensure starting-point calc takes finite time. Close gh-922.
Minor typo with Homebrew link. Close gh-929.
Initial draft of CONTRIBUTING.md
Second draft of CONTRIBUTING.md
CONTRIBUTING.md: fixes fragment url, #jquery-core-style-guide
CONTRIBUTING.md: adds top header
CONTRIBUTING.md: more contents links
Fix #12423. Ensure we can .apply() before we try.

I can't think of an uncontrived way to unit test this, it only occurs in IE when a BHO monkeys with the links.