allow imports and exports everywhere in loose mode

lib/6to5/file.js

@@ -244,7 +244,10 @@ File.prototype.parse = function (code) {
 
   code = this.addCode(code);
 
-  return util.parse(this.opts, code, function (tree) {
+  var opts = this.opts;
+  opts.looseModules = this.isLoose("modules");
+
+  return util.parse(opts, code, function (tree) {
     self.transform(tree);
     return self.generate();
   });

lib/6to5/util.js

@@ -218,14 +218,15 @@ exports.parse = function (opts, code, callback) {
     var tokens   = [];
 
     var ast = acorn.parse(code, {
-      allowReturnOutsideFunction: true,
-      ecmaVersion:                opts.experimental ? 7 : 6,
-      playground:                 opts.playground,
-      strictMode:                 true,
-      onComment:                  comments,
-      locations:                  true,
-      onToken:                    tokens,
-      ranges:                     true
+      allowImportExportEverywhere: opts.looseModules,
+      allowReturnOutsideFunction:  true,
+      ecmaVersion:                 opts.experimental ? 7 : 6,
+      playground:                  opts.playground,
+      strictMode:                  true,
+      onComment:                   comments,
+      locations:                   true,
+      onToken:                     tokens,
+      ranges:                      true
     });
 
     estraverse.attachComments(ast, comments, tokens);