parameter validator can handle custom deprecation warnings

lib/utils/parameter-validator.js

 var ParameterValidator = module.exports = {
   check: function(value, expectation, options) {
     options = Utils._.extend({
-      throwError: true,
-      deprecated: false,
-      onDeprecated: console.log,
+      throwError:         true,
+      deprecated:         false,
+      deprecationWarning: "Deprecated!",
+      onDeprecated:       function(s){ console.log('DEPRECATION WARNING:', s) },
       optional: false
     }, options || {})
 
@@ -36,7 +37,7 @@ var matchesExpectation = function(value, expectation) {
 var validateDeprication = function(value, expectation, options) {
   if (options.deprecated) {
     if (matchesExpectation(value, options.deprecated)) {
-      options.onDeprecated("Deprecated!")
+      options.onDeprecated(options.deprecationWarning)
       return true
     }
   }