Fixed typo in Vol2.tex
Added Policy Function Iteration tex file.
Merge branch 'policy' of https://github.com/jhendr/numerical_computing into policy
Made initial draft of first part of policy function lab.
Added a small amount of content and problems to policy lab.
Completed draft of Policy Function Iteration lab and added to Vol2.tex.
Merge pull request #65 from jhendr/policy

Draft of Policy Iteration Lab