Rename args to be consistent with usage tool

[mgood]

The CLI args should be more consistent with how they're defined in usage itself, e.g.

      --usage-bin <USAGE_BIN>
          Override the bin used for calling back to usage-cli

          You may need to set this if you have a different bin named "usage"

          [env: JDX_USAGE_BIN=]
          [default: usage]

      --usage-cmd <USAGE_CMD>
          A command which generates a usage spec e.g.: `mycli --usage` or `mycli completion usage` Defaults to "$bin --usage"