Handle pre-calculated results as input and historical results (t < 0)

[hearnderek]

in what format to accept it

dataframe and dictionary

Internal Data

Ideas:

1. [bad] put data at end of the list so negative numbers give the expected results
2. put data into a dictionary instead of a list.

[hearnderek]

This is also related to injecting data into our calculations. The most obvious example is filling t=0 to simplify user functions which reference date at t-1