Merge branch 'release/0.3.2' into develop
raise Tokyo::Locked when threading error
speed up Kvs::Tokyo::Cabinet#read!
[spec] Kvs::Tokyo::Cabinet#read!
Kvs::Tokyo::Cabinet#first
each_keys is deprecated and will be removed in 0.4.0
0.3.3 speed up Kvs::Tokyo::Cabinet#read!
Merge branch 'release/0.3.3'