disable openssl call in md5 calculation;

add prefix cache to avoid unnecessary synchronous folder creation;

add pause/resume control in file creation, significantly reduce
memory usage in node
use rename to update hard link in creation (previouly using ln -f which was not atomic);
use rename to atomically update enumeration and quota files
Optimize enumeration compactor speed; make compactor tunable;
set enumeration cache expiration to a longer period
change internal folder oragnization to "<two digits of hash>/<one digits of hash>" to save inodes and space; NOTE: INCOMPATIBLE with previous revisions
drop legacy code and update documentation
update documentation
fixing various gc race conditions
Start streaming to temp file immedirately to optimize file creation throughput; updated gc correspondingly; added throttling to slow down upload if gc cannot catch up; slightly tuned gc/ec intervals
compress enumeration data to optimize overall performance; now using node 0.8 version and zlib
fix default config file
using ts in file name instead of doing stats in gc
queue list queries when loading the enumeration file
fix indentation and avoid unnecessary reading enum file if there is no work
better error handling when not enough disk space in file_create; remove openssl related code
fixing reading/writing corrupted delta files; give up on writing incomplete base file
fixing a typo in ec (which results in incorrect replay); fixing hash-key lookup in ec (which results in incorrect recovery)
fix incomplete write problem in gc/ec; add a tool to manually recover enumeration info from blob
more error handling in ec
not overwrites for puts; better support for multi-versioning in future; global_ordering to significantly optimize enumeration and gc; puts are working now, delete/copy/list are broken
read works; start a web server in ec to return object versions for reads