changed onSave() -> onSave(bool&)
rename 'loaded' signal to 'loadFinshed' to be consistent with 'saveFinished' signal
added signal 'onSaveAs' and corresponding
added functions: 'emitSaveReportAs', 'emitLoadFinished'
DesignWidget:
add boolean functions checking whether emitSaveReport and emitSaveReportAs completed.
DesignWindow:
save / saveas / load functions are interceptable by reportengine signals