Adds `contents` and `wrapInner`.

- http://api.jquery.com/contents/
- http://api.jquery.com/wrapInner/
Improve tests for `contents` and `wrapInner` by confirming the existence of expected elements.
Use $.fn.concat instead of [].concat in flatten() function.
To make zepto work in IE9, we need to override ugly native concat behavior. Without the change, that can be done only by changing Array.prototype. With it, we can surgically strike at $.fn.concat.

Other instances of concat in zepto are not problematic, as they either already run the fn version (like one in $.fn.add), or are called only on plain arrays (two instances in event handling code).
fix tests in Firefox
Merge pull request #516 from romanrudenko/patch-2

Use $.fn.concat instead of [].concat in flatten() function.
Merge pull request #512 from johnboxall/adds-contents-and-wrapinner

Adds `contents` and `wrapInner`.
add $.parseJSON
stops blocking scroll on body in touch_functional
enables locking an element to no-scroll (preventdefault on touchmove) or allowing scroll after touch (eg for buttons), scrolling after touch cancels all tap events.
cancels swiping in the same direction as a scroll
implements cancelTouch() on 'tap' event, allowing simple button actions to respond very quickly, without the 250ms delay of singleTap, while also allowing scrolling so long lists or buttons won't break page navigation.
updates tests to do everything async, updates touch to fix some logic errors with single/double tapping. TODO: touch.js minor refactor
adds comments to touch.js on async and logic changes
stylistic fixes
Corrected parameters of `load` success callback to match docs and jQuery. Fixes issue #545.
Fixed spacing.
Merge pull request #551 from bnickel/545-load-params

Corrected parameters of `load` success callback to match docs and jQuery...
fix whitespace
Support rake building with Ruby 1.8, fixes https://github.com/madrobby/zepto/issues/559
Merge pull request #563 from thorlarholm/master

Fix for issue #559