Fixing hanging-comma and adding autoload key

Just a small fix and small addition:

* The extra comma after the version is bad JSON - it should make Composer sad :/

* The autoload config will allow the Zencoder classes to be autoloaded without any trouble

Thanks!

Author: weaverryan

composer.json

@@ -6,7 +6,12 @@
   "type":"library",
   "license":"MIT",
   "require": {
-    "php": ">=5.2.0",
+    "php": ">=5.2.0"
+  },
+  "autoload": {
+    "psr-0" : {
+      "Services_Zencoder" : ""
+    }
   },
   "authors":[
     {