Optimisation: Use String instead of window.String. Close gh-1176.

Follows-up 22e28b01e60e87b2454f88ca128fb84916b13564.
Fix #13471. $().on(".xyz"...) should avoid later crash.

If the event type is an empty string we end up hanging in .off() which makes for
mighty hard debugging. Instead treat it as a no-op. Docs seem clear this is not
allowed.
Whitespace.
Fix #13494: Fallback defineProperties to jQuery.extend. Close gh-1182.

Android<4 (ancient WebKit) doesn't have full ES5 support.
Ref #13283, move .andSelf() to deprecated.js. Close gh-1170.
No ticket: Squeeze data