Consolidate header LaTeX into its own file

This commit does some bookkeeping and cleans up the input, usepakage
etc commands. It also puts package loading and macro definitions into
a single LaTeX file.
Add recursive window simulations for separate appendix
Cache tizk graphs externally

This commit adds LaTeX code to avoid recalculating the Tikz code
for graphs, which speeds up compilation.
Remove 1000 obs monte carlo

This monte carlo exercise filled the disk with simulated paths, so
it doesn't really work for the recursive mc.