Implement disequilibrium

[kahaaga]

Rosso, O. A., Larrondo, H. A., Martin, M. T., Plastino, A., & Fuentes, M. A. (2007). Distinguishing noise from chaos. Physical review letters, 99(15), 154102.

This quantity is also used in combination with 2D permutation entropy (#74).

[kahaaga]

I have an implementation of this based on #73 that I will re-do once the new implementation is reviewed and merged

[kahaaga]

This is moved to Complexity.jl