Move digestLengthForAlgorithm to OTPAlgorithm
Move password generation to a category on OTPToken
Move -generateOTP into OTPToken+Generation
Move -generateOTPForDate: into OTPToken+Generation
Consolidate -generatePasswordForDate: into -generatePassword
Move -generatePasswordForCounter: into OTPToken+Generation
Remove the now-defunct OTPGenerator class
Consolidate counter updates from -generatePassword into -updatePassword
Don't cache the token password (generating it is idempotent)
Ensure that -password always returns an up-to-date value for timer-based passwords
Use KVO instead of notifications to update cells
Fire the TOTP update timer only once per second.
Merge branch 'generation'