Inverse Fisher Transform of NWMA Aroon Oscillator

As originally described by Manfred G. Dürschner. Applies an inverse fisher transform to an aroon oscillator calculated using smoothed price. Smoothing is done via NWMA or "Moving Average 3.0".

Signals are Buy > 0 and Sell < 0

length 1 must be at least twice length 2 (lambda >= 2.0)