No ticket: Reduce size in anticipation of Sizzle-free builds
(cherry picked from commit dbf3056b250bbc279fa947031181f9e25a40bacf)
No ticket: Revise unit tests in anticipation of Sizzle-free builds
Fix #13499: selector with leading ID matching only a name
(cherry picked from commit 5c4ab97a64c162503ac200bc7cea7f3e5725984d)
No ticket: Restore support for Android<4.0
Fix #13505: Yet another detached add patch
No ticket: reduce support.js
No ticket: move jQuery.expando to core
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.