v0.1.6

Adds additional Measurement types

1. Simple Exponential Moving Average - uses a single alpha value to tune this
2. Simple Moving Variance - uses to Simple Exponential Moving Averages to calculate the variance
3. Windowless Moving Percentile - Much credit goes to Martin Jambon here: https://mjambon.com/2016-07-23-moving-percentile/ This is an O(1) (time & space) implementation of a percentile approximation of an input signal.