Fixed missing MVC mapping for getting test state

For some reason I had forgotten to add the required handler
to the MVC CandidateTestController to enable the test state to be
downloaded (by authors). This is fixed here.
Updated jQuery/UI library versions

This fixes the strange "white stripe" phenomenon
under jQuery UI pop-up dialog boxes.
Some minor test rendering tweaks

Moved the test session control further up so that it is nearer the
item control buttons, hopefully making it easier for candidates to
notice them. Also did a bit of tidying to the confirm text when passing
through a point of no return in the test (e.g. end test part). Plan to
make these use nicer dialogs next, though.
Renamed QtiWorksRendering.submit() -> maySubmit()
XSLT adapter now safely handles null delegate