Make mustache.mjs work with Deno

Minor adjustments needed to make the TypeScript compiler
that is built into Deno, be happy with how mustache.js'
ES module source looks in terms of function parameters
passed and object mutability.

Refs #1

mustache.js

@@ -3,7 +3,7 @@
   typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
   typeof define === 'function' && define.amd ? define(factory) :
   (global = global || self, global.Mustache = factory());
-}(this, function () { 'use strict';
+}(this, (function () { 'use strict';
 
   var version = "3.1.0";
 
@@ -529,7 +529,7 @@
    */
   Writer.prototype.render = function render (template, view, partials, tags) {
     var tokens = this.parse(template, tags);
-    var context = (view instanceof Context) ? view : new Context(view);
+    var context = (view instanceof Context) ? view : new Context(view, undefined);
     return this.renderTokens(tokens, context, partials, template, tags);
   };
 
@@ -654,7 +654,15 @@
   var mustache = {
     name: 'mustache.js',
     version: version,
-    tags: [ '{{', '}}' ]
+    tags: [ '{{', '}}' ],
+    clearCache: undefined,
+    escape: undefined,
+    parse: undefined,
+    render: undefined,
+    to_html: undefined,
+    Scanner: undefined,
+    Context: undefined,
+    Writer: undefined
   };
 
   // All high-level mustache.* functions use this writer.
@@ -717,4 +725,4 @@
 
   return mustache;
 
-}));
+})));