add persist support
new type - bin
fix problem of size calculation in bin type, and add 'btail' api
add persist command
update doc
move redid-cli to cmd
add commands doc
update commands doc
add repair support
update commands document
newly support of bit operation 'and' and 'or' for the bin type
Merge branch 'develop' of https://github.com/siddontang/ledisdb into develop
fix the problem causes from using a global empty segment
repair bugfix
solve bitop problem while inexisting srckeys occours
add hmclear, lmclear and zmclear for multi keys
move bin to another branch
move client to client branch
expire bug fix
update document