Log Message:
Version 2.8 (released 2012-06-15)

 * ykclient: Add C++ namespace protection.

 * Add multi-server support with curl_multi.
   Enabled by default for YubiCloud servers.
   Settable with the new library function set_template_urls() or
   the urls parameter to ykclient_verify_otp_v2().

 * Remove extra % in ykclient help.

 * Add ca path option to ykclient, --ca.
   Patch from Jay Kline <jay.kline.ctr@hpcmo.hpc.mil>.

 * Make the nonce unique for consecutive calls to the same ykclient handle.

 * Do url encoding of OTP before sending.

 * Fix segfault on curl error.
   Patch from Lee Hinman <lee.hinman.ctr@hpc.mil>