[Feature Request] Add quiet modes.

[bmfrosty]

For use in cron jobs, I only want output if there's an error (can't set up, log in, get platforms, etc...), or if there's an attempt (successful or not) at redeeming a code.

I assume there are others that only want output on an error.

I'm going to accomplish what I want out of this with a bit of grep, but I feel like it might be worth having directly. I propose 3 quiet levels.

q - for cron jobs. Output only on code redemption attempt or error.
qq - Output only on error or code redemption failure.
qqq - no output, just an exit code.