Functional Compression

This project is to construct a new type of column group in the compression framework.
This column group has to approximate the input vector with a function, such that
it can reconstruct the original value.

https://en.wikipedia.org/wiki/Curve_fitting
https://en.wikipedia.org/wiki/Regression_analysis

The fundamental function to implement is a mapping from a row index to a value. such that
one can ask what value is at row index 1000.

As an simple example if a column contains an incrementing value, of
1 2 3 4 5
then the function should simply return the row index inputted.

The first example could result in a colgroup called LinearFunctionalColGroup.
then further groups like:
PolynominalFunctionalColGroup,
FourierTransformFunctionalColGroup,