MXS-1300: Fix duplicated options

Moved the option declaration to the main source file. Added default
functions for all modules to catch unknown command invokations. Cleaned up
and exposed more ways to use the doRequest function.

client/maxctrl/lib/show.js

@@ -83,5 +83,8 @@ exports.builder = function(yargs) {
                 {'Commands': 'attributes.commands'}
             ])
         })
+        .command('*', 'the default command', {}, () => {
+            console.log("Unknown command. See output of 'help show' for a list of commands.")
+        })
     .help()
 }