storage optimization

[abose]

• We store everything as JSON while the underlying Memcached accepts bin data. This leads to less storage under utilization.
  For Eg. Set('key", 1) will result in json storage overheads as it is stored as a string instead of a 4 byte INT

Options

1. Use a binary format and see what impact we have on size. Eg: https://www.npmjs.com/package/bson
2. use a custom serializer in memjs to write bin data.