Add Christophe Devine's sha256 code (GPL)
Match sha256 headers to sha1
Add hmac_sha256
Make generate.c use sha256 if secret key longer than 48 chars
Add missing include
More declaration fixes
Fix AMQueueFail error message
Maximize in/out message sizes
Allow up to 64 chars in secret key
Merge pull request #5 from ibrado/master

SHA256 for pTOTP (AWS 64 char keys)