ENH: Add itkLogGaborFreqImageSourceTest content.
ENH: Clamp Butterworth cutoff frequency.
ENH: LogGaborFreqImageSource inherits from GenerateImageSource.
ENH: Add LogGaborFreq baseline.
STYLE: Use ITK_OVERRIDE in LogGaborFreq.
ENH: Remove unused Ranges member.
BUG: Print out LogGaborFreq members in PrintSelf.
ENH: Cleanup LogGaborFreqImageSource ThreadedGenerateData.