MXS-1300: Make MaxCtrl more like a library

All invocations into the common helper functions are now done through the
`maxctrl` function. This allows the program arguments to be passed to the
core as a parameter instead of reading them from global variables.

This helps with the implicit initialization that was done when the yargs
library was required which caused duplicated output.

Refactored the core functions so that they only process the argument
vector. The parsing of the argument vector is done in maxctrl.js where it
is more appropriate.

maxctrl/common.js

@@ -18,8 +18,11 @@ var Table = require('cli-table');
 module.exports = function() {
 
     this._ = require('lodash-getpath')
-    // Common options for all commands
-    this.program = require('yargs');
+
+    this.maxctrl = function(argv) {
+        this.argv = argv
+        return this
+    }
 
     // Request a resource collection and format it as a table
     this.getCollection = function (resource, fields) {
@@ -114,11 +117,10 @@ module.exports = function() {
     }
 
     // Helper for converting endpoints to acutal URLs
-    this.getUri = function(host, endpoint) {
+    this.getUri = function(host, secure, endpoint) {
         var base = 'http://'
-        var argv = this.program.argv
 
-        if (argv.secure) {
+        if (secure) {
             base = 'https://'
         }
 
@@ -127,12 +129,12 @@ module.exports = function() {
 
     // Helper for executing requests and handling their responses
     this.doRequest = function(resource, cb, obj) {
-        pingCluster()
+        pingCluster(this.argv.hosts)
             .then(function() {
-                var argv = this.program.argv
+                var argv = this.argv
                 argv.hosts.forEach(function(host) {
                     args = obj || {}
-                    args.uri = getUri(host, resource)
+                    args.uri = getUri(host, argv.secure, resource)
                     args.json = true
                     args.timeout = argv.timeout
 
@@ -206,10 +208,10 @@ function pingMaxScale(host) {
     })
 }
 
-function pingCluster() {
+function pingCluster(hosts) {
     var promises = []
 
-    this.program.argv.hosts.forEach(function(i) {
+    hosts.forEach(function(i) {
         promises.push(pingMaxScale(i))
     })