S3 backend support.
CMake fixed to work with upload_s3 for unit tests.
S3fanout is now Singleton.
Code cleaned: CURL now only in s3fanout.
Parallell uploads limiting works.
Libcurl code in one loop.
Removed unneccessary pipes and variables.
Timeout handling added - again.
S3 configured through config file.
S3 configuration reading is now also cleaned.
Upload errors are now detected.
Multi account and bucket support added to config file (s3.conf).
S3 configuration uses now also port parameter.
Merge branch 'master' of https://github.com/ssheikki/cvmfs