Don't break the back/forward cache. Fixes #959

Attaching an unload listener breaks the back/forward cache in modern
browsers, and is only necessary in old versions of IE that can leak
memory across pageviews if events aren't detached.
ButtonGroup.disable disables all child buttons / inputs
See #973
Bump version to 3.12.0pre
Merge branch 'dev-3.x' of github.com:yui/yui3 into dev-3.x
Merge branch 'dev-master' into dev-3.x
Merge branch 'event-bfcache' of git://github.com/rgrove/yui3 into dev-3.x
Build event.
Update Event history.
Merge branch 'button-group-disable' of git://github.com/asystance/yui3 into dev-3.x
Build button.
Merge branch 'dev-master' into dev-3.x
Merge branch 'dev-master' into dev-3.x
Build unbuild modules.
added options to sort() and _sort()
updated tests for sortingOptions
included descending option in private _sort
Fixed NPE on EventTarget.detach('cat|*')

The exception was coming from the private `_getType(type, pre)` method.

We removed the typeof string check in `getType`, for performance reasons
in 3.10.0, since the calling code had it covered already and it sits on many
critical paths.

However there's one path, for the 'cat|*' star case with a prefix configured,
where a null `type` is passed to `_getType` and it was barfing on the `type.indexOf()`
call as a result.

Re-added a simple truthy check (still avoiding the typeof string) before calling
indexOf.
Merged in fix for detach(cat|*)
Build for detach(cat|*) fix
Merged detach(cat|*) fix from dev-master. Required simpleyui rebuild due to min conflicts