=== 0.1.0 / 2013-02-04

* Initial release:
** Delay line
** Biquad filters
** Envelope detector
** Conversion from dB-linear and linear-dB
** Linear interpolation
** Oscillator with selectable wave type (sine, square, triangle, sawtooth)

=== 0.1.1 / 2013-02-04

Add EnvelopeDetector#attack_time= and EnvelopeDetector#release_time=

=== 0.1.3 / 2013-02-18

* Added:
** A .cubic_hermite method to Interpolation class (implements cubic hermite polynomial interpolation)
** Window classes (Blackman, Hann, Hamming, etc.)
** DFT class, with .forward and .inverse methods.
** FFT class, with .forward and .inverse methods.
** Windowed sinc filter, a FIR filter for lowpass and highpass-
** Dual windowed sinc filter, a FIR filter for bandpass and bandstop.
** Discrete and Polynomial resampling classes, each with an .upsample method.
** Plotter class to make graphing with gnuplot easier. Has #plot_1d and #plot_2d methods.
** Signal class for testing convenience. Contains signal data and has convenience methods for plotting, correlation, energy, etc.

=== 0.1.4 / 2013-02-19

Fixed gemspec to always depend on gnuplot (not just for development).

=== 0.1.5 / 2013-02-19

Adjust project documentation.

=== 0.1.6 / 2013-03-21

Update to be compatible with hashmake-0.1.6.

=== 0.1.7 / 2013-04-18

Require all sample rate args to be Fixnum.

=== 0.1.8 / 2013-05-03

Add Envelope and Extrema classes, for signal analysis.

=== 0.1.9 / 2013-05-06

Add TukeyWindow.
Add Signal#keep_frequences, Signal#remove_frequencies, and Plotter#plot_signals.

=== 0.2.0 / 2013-05-21

Add instance methods to Signal class: #duration, #normalize, #derivative, #lowpass, #highpass, #bandpass, #bandstop, #plot_1d, and #plot_2d.
Add Correlation class to find similarity between signals (used to find a feature in an image).
Make envelopes smoother with polynomial upsampling. In Signal#envelope and Signal, always return a Signal object (so also remove make_signal flag).