- don't hard-code the group as the first passed account
- token::approve() banks for each token vault
- sign for each bank
- deal with using tokens without an existing position
- handle deactivation of token account if balance goes to 0
This guarantees stability when a gov proposal adds a new token and a new
market in one transaction. This way the RegisterMarket instruction knows
exactly what index the new token will have.
Previously, the new token index was generated automatically, meaning
you couldn't be sure what index a new token would get in advance.
Christian Kamm
microwavedcola1