Update calvo lecture with new visualizations and updated content (#164)

* Tom's June 13 edits of calvo lecture in branch

* update graphs and include beta and c in the class

* rename to calvo

* fix a small typo

* update graphs for change beta and c

* update graph for v and v_check

* update graphs requested

* Tom's June 18 edits of calvo lecture

* Tom's June 19 edits of calvo.md lecture

* verify J(\theta) and V(\theta)

* tom's June 20 edits of calvo.md lecture

* Tom's June 21 edits of calvo.md

* update calvo and graph

* Fix label location

* Tom's June 22 edits of calvo.md lecture

* refine notations and graphs

* Tom's edits June 23 of calvo.md

* update code notation and add experiments with alpha=4

* Tom's June 23 next edit of calvo.md

* Update table and code. Experiment with table rendering on server

* update code for tables

* Tom's June 25 edits of calvo.md

* Tom's June 26 edits of calvo.md

* hide long code for visualization

* remove content directory

* simplify code

* vectorize the `compute_value_and_policy` method

* update small typos and use italics for emphasise

---------

Co-authored-by: thomassargent30 <[email protected]>

Author: HumphreyYang