Code tidy

Deleted unnecessary code for capture matrices and useless stat code.
Began putting new stat code in for JS that takes capture matrix as
input.
Calculate marked function

Can now calculate number of previously marked animals in final sample of
capture matrix.
JS estimator

Finished JS estimator. Fixed bugs in analysis of CR Robust estimator.
Note that JS estimator is consistently low for early time - check that
statistics calculated correctly (haven't checked Z properly yet).