Merge the QJSEngine and QJSValue development branch into master.

This replaces the dependency to QtScript with two new builtin classes
QJSValue and QJSEngine.

This is still work in progress, development continues now in the master branch.

Change-Id: I7f5487feb45c972f25a22b10cc81b9218b9805de
Reviewed-on: http://codereview.qt.nokia.com/2299


Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Simon Hausmann <simon.hausmann@nokia.com>