Fix for issue #517.

Now when compiiled with amd option and a single input argument, we are
checking to see whether the input is a file or folder.

bin/handlebars

@@ -168,10 +168,14 @@ function processTemplate(template, root) {
     if (argv.simple) {
       output.push(handlebars.precompile(data, options) + '\n');
     } else if (argv.partial) {
-      if(argv.amd && argv._.length == 1){ output.push('return '); }
+      if(argv.amd && (argv._.length == 1 && !fs.statSync(argv._[0]).isDirectory())) {
+        output.push('return ');
+      }
       output.push('Handlebars.partials[\'' + template + '\'] = template(' + handlebars.precompile(data, options) + ');\n');
     } else {
-      if(argv.amd && argv._.length == 1){ output.push('return '); }
+      if(argv.amd && (argv._.length == 1 && !fs.statSync(argv._[0]).isDirectory())) {
+        output.push('return ');
+      }
       output.push('templates[\'' + template + '\'] = template(' + handlebars.precompile(data, options) + ');\n');
     }
   }
@@ -184,7 +188,7 @@ argv._.forEach(function(template) {
 // Output the content
 if (!argv.simple) {
   if (argv.amd) {
-    if(argv._.length > 1){
+    if(argv._.length > 1 || (argv._.length == 1 && fs.statSync(argv._[0]).isDirectory())) {
       if(argv.partial){
         output.push('return Handlebars.partials;\n');
       } else {