1-D Gaussian peak and valley detector

Detects peaks and valleys in a 1-D signal

The algorithm takes in a 1-D signal and finds the Gaussian derivative of it with the given kernel size and sigma, to provide the zero crossings. The zero crossings are then analyzed to give peaks and valleys. In order to remove very closely situated peaks and valleys, a width (provided by the user) places a constraint on how close the peaks and valleys can be.