Navigates to the home position for the edit.

def gotoHome(self):
        """
        Navigates to the home position for the edit.
        """
        mode = QTextCursor.MoveAnchor
        
        # select the home
        if QApplication.instance().keyboardModifiers() == Qt.ShiftModifier:
            mode = QTextCursor.KeepAnchor
        
        cursor = self.textCursor()
        block  = projex.text.nativestring(cursor.block().text())
        
        cursor.movePosition( QTextCursor.StartOfBlock, mode )
        if block.startswith('>>> '):
            cursor.movePosition(QTextCursor.Right, mode, 4)
        elif block.startswith('... '):
            match = re.match('...\s*', block)
            cursor.movePosition(QTextCursor.Right, mode, match.end())
        
        self.setTextCursor(cursor)