Nilbot meets Bovespa

Nilbot also knows Bovespa (BVMF).
And a little refactor, for the sake of code reusability.
Fix indentation

Replace the remaining tabs with spaces.
Add !nyse command

For stocks based in New York.
results-from-quote: Also handle l value

The l contains the current value of currency conversions.
Command usd added

Returns the current value of USD in BRL.