editor.

d914555badc in qt-dui/master removed QmlType::fromObject. This
patch replaces the method with QVariant::fromValue. The difference
here is that the QVariant type is always QObject*, instead of
the real inherited type. We have yet to verify if this breaks something.

Depending on the Qt version we might be able to gather the qemu path,
if not the former error message was a bit misleading.

Reviewed-by: kh1

Reviewed-by: Friedemann Kleint <qtc-committer@nokia.com>

	modified:   src/plugins/debugger/registerwindow.cpp

Reviewed-by: Roberto Raggi <qtc-committer@nokia.com>

	modified:   src/libs/qmljs/qmljsinterpreter.cpp

This hopefully brings the navigation history back to behaving sensibly.

the last step was moving the statics to a common class which is
initialized at startup.

Save some cycles by not using QTextBlock::text unnecessarily (since only
its length and the character at the block position were used).

This is to make it consistent with the rest of the settings ui.
When a checkbox is unchecked, the sub-check box becomes invalid, its
functionality is disabled, but it retains its checked state.