'Displays specified message on button to let user know the action is in progress. Threadsafe.'

def processing(self, message='Processing..', tip='', processEvents=True):

    isGuiThread = (QtCore.QThread.currentThread() == QtCore.QCoreApplication.instance().thread())
    if isGuiThread:
        self.setEnabled(False)
        self.setText(message, temporary=True)
        self.setToolTip(tip, temporary=True)
        if processEvents:
            QtGui.QApplication.processEvents()
    else:
        self.sigCallProcess.emit(message, tip, processEvents)
