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.mjs

@@ -3,8 +3,9 @@
  * http://github.com/janl/mustache.js
  */
 
-import { version } from './package.json';
+import _package from './package.json';
 
+var version = _package.version;
 var objectToString = Object.prototype.toString;
 var isArray = Array.isArray || function isArrayPolyfill (object) {
   return objectToString.call(object) === '[object Array]';
@@ -522,7 +523,7 @@ Writer.prototype.parse = function parse (template, tags) {
  */
 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);
 };
 
@@ -647,7 +648,15 @@ Writer.prototype.rawValue = function rawValue (token) {
 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.
@@ -708,4 +717,4 @@ mustache.Scanner = Scanner;
 mustache.Context = Context;
 mustache.Writer = Writer;
 
-export default mustache;
+export default mustache;