fix(@angular/cli): allow usage of hidden command options

Author: clydin

Diff for: packages/@angular/cli/tasks/schematic-get-options.ts

@@ -34,7 +34,6 @@ export default Task.extend({
     const keys = Object.keys(properties);
     const availableOptions = keys
       .map(key => ({...properties[key], ...{name: stringUtils.dasherize(key)}}))
-      .filter(opt => opt.visible !== false)
       .map(opt => {
         let type;
         const schematicType = opt.type;
@@ -70,7 +69,8 @@ export default Task.extend({
           type,
           schematicType,
           default: undefined, // do not carry over schematics defaults
-          schematicDefault
+          schematicDefault,
+          hidden: opt.visible === false,
         };
       })
       .filter(x => x);