Exposing option to hide MISSING_IN_SCHEMA mismatches by default

lib/options.js

@@ -106,6 +106,15 @@ module.exports = {
           ' Must be sent as an array of strings. Valid inputs in the array: PATHVARIABLE, QUERYPARAM,' +
           ' HEADER, BODY, RESPONSE_HEADER, RESPONSE_BODY',
         external: true
+      },
+      {
+        name: 'Whether MISSING_IN_SCHEMA mismatches should be returned',
+        id: 'showMissingInSchemaErrors',
+        type: 'boolean',
+        default: false,
+        description: 'MISSING_IN_SCHEMA indicates that an extra parameter was included in the request. For most ' +
+          'use cases, this need not be considered an error.',
+        external: true
       }
     ];