Add a lecture on asset prices

[jstac]

Show

• long run trends
• returns on different asset classes
• higher expected returns usually means higher volatility -- suggests risk aversion
• how predictable are returns?
• share prices vs business cycles --- leading indicator?

[Smit-create]

@jstac So simplifying this one: https://python.quantecon.org/markov_asset.html would work? I can work on this if no one else is assigned.