Linear least squares phase estimation of a sine wave

This snippet extracts the phase out of a noisy sinusoidal signal. The algorithm is a clever linear least squares (LLS) scheme, courtesy of the IEEE waveform measurement standard for characterizing ADCs and DACs. It works in spite of the fact that the sine wave is non-linear -- which just underscores the point that the linear bit of LLS is linearity in the parameters, not the fit function. It works quite a bit faster than the Levenberg-Marquardt nonlinear least squares routine.