Numerical Integration:
Links:
- http://www.originlab.com/doc/Origin-Help/Math-Integrate
- http://math.stackexchange.com/questions/344073/integrating-non-uniform-grid-data-from-an-accelerometer
- https://github.com/uwhpsc-2016/homework3/issues/7 (modified Simpson's rule)
- https://github.com/scipy/scipy/blob/v0.18.1/scipy/integrate/quadrature.py#L329-L433