support base32 padding

[ESPINS]

support base32 padding

[tilkinsc]

1. test/main.c - I have no idea if sha256 actually works in the first place, its implementation has been guessed on, not verified. I have swapped your edit over to sha1, as these test files serve more as a demonstration and an easy catch when something breaks while developing. Further, I had to change the totp_at to point to the correct code for the generation as produced by another implementation.

2. test/main.cpp - This file got little love, so I added the same test. It's important to me that these two tests provide the same exact results.

3. cotp.c otp_byte_secret - Its better to break when c == '=' rather than burning through the rest of the string. For example a string with a 256 buffer who has 8 characters will be padded with 256-8 characters, needlessly burning through the rest of the string. (there should be no embedded =) We need to be responsible for correctly handling the length of the base32_secret because we do not burden the user with providing the length of the base32_secret.

Thank you for your contribution!