Stocks.Prices.get_quote_rh -- Active/after/closed pricing picker

[lockefox]

Current code does a crappy job picking the correct current_price value between last_trade_price or last_extended_hours_trade_price.

Also, the current method requires the code to hit /markets and /market/[NAME]/hours/[DATE] every time a quote is requested. Each request can take ~1s, and we already need 3 to make quotes from Robinhood.

• Improve price picking method (and testability)
• Add a tinydb, tinymongo or sqlite inline DB for caching today, and throwing away yesterday
• Enumerate market status (open, after hours, closed, holiday)