"requireUsernameProofs" feature flag
Update config values
Merge pull request #51 from stellar/feature-flags

"requireUsernameProofs" feature flag
Sets totp window to 1, adds test to confirm code expiration
Rounds totp grace period checking to nearest second
Merge pull request #52 from stellar/fix-totp-window

Reduce TOTP code max-age to 60 seconds
Merge branch 'master' into emails

Conflicts:
	config/development.json
	config/test.json