Gets the parameter values

        :returns: dict of inputs:
        |        *'nfft'*: int -- length, in samples, of FFT chunks
        |        *'window'*: str -- name of window to apply to FFT chunks
        |        *'overlap'*: float -- percent overlap of windows

def values(self):
        """Gets the parameter values

        :returns: dict of inputs:
        |        *'nfft'*: int -- length, in samples, of FFT chunks
        |        *'window'*: str -- name of window to apply to FFT chunks
        |        *'overlap'*: float -- percent overlap of windows 
        """
        self.vals['nfft'] = self.ui.nfftSpnbx.value()
        self.vals['window'] = str(self.ui.windowCmbx.currentText()).lower()
        self.vals['overlap'] = self.ui.overlapSpnbx.value()
        return self.vals