* add cas/cad commands
* feat(command): Add SetIFDEQ, SetIFDNE and *Get cmds
Decided to move the *Get argument as a separate methods, since the
response will be always the previous value, but in the case where
the previous value is `OK` there result may be ambiguous.
* fix tests
* matchValue to be interface{}
* Only Args approach for DelEx
* use uint64 for digest, add example
* test only for 8.4
