Fix export I/F
Add LRU NIF imples
Add iterator I/Fs AND handling journal file logic(50%)
Impl handling data files(20%)
Impl handling data files(40%)
Impl handling data files(60%)
Impl handling data files(90%). Rest of tasks are error handlings/eunits
fixed README.md to much with current implementations
Optimized slab params for small datas AND Refactor
Added FD close checks
Made Key S3-compaticle
Added auto journal rebuild when exceeding a certain threshold
Fixed specifications about a length of Key
Done UT/IT
Done Benchmarks AND eprof
Roll version 0.2.0
Merge branch 'release/0.2.0'