Update jquery.ui Vector theme to 1.9.2

Update jquery.ui Vector theme to 1.9.2

Follows-up 3cb2ccd87863abb8a99ed7d970730ae9e4138fcc.

Various structural changes were made in jQuery UI 1.9, and the Vector
theme was not updated to accommodate for those changes.

There have also been lots of small improvements to the base theme (which
is substituted inside the Vector theme) that were made over the past few
releases that weren't backported (such as Ib099282484b for bug 67243).

And there were two new modules in jQuery UI 1.9 (menu and spinner) that
were lacking Vector theme stylesheets.

Change-Id: I27accab309da063f4d7965a103951b152e77937d