Remove "spender" and "to" from "submit"

[mootz12]

Having a single "spender" and "to" for a vector of requests is too restricting.

For each action, the user acted against should be able to be specified.

For actions where tokens are being input into the protocol, the "user" would be the spender, and would need to authorize the transactions.

For actions where tokens are being sent out of the protocol, the "user" would be to, and would not need to authorize the transactions.

Technical Notes

This might cause some confusion when designing the Request object for use with filling liquidations.