add the same warnings package used in yubico-c
as curl_ret is a CURLMCode, use CURLM_OK instead
use size_t for looping to avoid warnings
move up declarations and convert loop variable to size_t to avoid warnings
snprintf returns an int, check if it's negative
cast ykc->key to const unsigned char to keep constness
code is never used, remove it and move other declaration up
assign out so we can be sure it's assigned before return
add travis continuous-integration configuration
add whitelisting of AM_PROG_AR to work with automake 1.12
add test cases for hmac-sha1 from rfc 2202
Silence warning in automake >= 1.12