fix(container): factories are explicit

Factories should be rarely used, so the normal is constructors.
Factories are now explicitly indicated with Factory metadata. This
should also fix minification issues. Fixes #13

src/container.js

@@ -1,9 +1,22 @@
 import {Metadata} from 'aurelia-metadata';
-import {Resolver, Registration} from './metadata';
-import {isClass} from './util';
+import {Resolver, Registration, Factory} from './metadata';
 
 var emptyParameters = Object.freeze([]);
 
+// Fix Function#name on browsers that do not support it (IE):
+function test(){}
+if (!test.name) {
+  Object.defineProperty(Function.prototype, 'name', {
+    get: function() {
+      var name = this.toString().match(/^\s*function\s*(\S*)\s*\(/)[1];
+      // For better performance only parse once, and then cache the
+      // result through a new accessor for repeated access.
+      Object.defineProperty(this, 'name', { value: name });
+      return name;
+    }
+  });
+}
+
 /**
 * A lightweight, extensible dependency injection container.
 *
@@ -270,16 +283,16 @@ export class Container {
       throw error;
     }
 
-    if(info.isClass){
+    if(info.isFactory){
+      return fn.apply(undefined, args);
+    }else{
       context = Object.create(fn.prototype);
 
       if('initialize' in fn){
         fn.initialize(context);
       }
 
       return fn.apply(context, args) || context;
-    }else{
-      return fn.apply(undefined, args);
     }
   }
 
@@ -312,7 +325,7 @@ export class Container {
   }
 
   createConstructionInfo(fn){
-    var info = {isClass: isClass(fn)};
+    var info = {isFactory: Metadata.on(fn).has(Factory)};
 
     if(fn.inject !== undefined){
       if(typeof fn.inject === 'function'){

src/index.js

@@ -13,10 +13,11 @@ export {
   Lazy,
   All,
   Optional,
-  Parent
+  Parent,
+  Factory
 } from './metadata';
 
 export {Container} from './container';
 
 Metadata.configure.classHelper('transient', Transient);
-Metadata.configure.classHelper('singleton', Singleton);
+Metadata.configure.classHelper('singleton', Singleton);

src/metadata.js

@@ -254,3 +254,11 @@ export class Parent extends Resolver {
     return new Parent(key);
   }
 }
+
+/**
+* An annotation used to indicate that a particular function is a factory rather than a constructor.
+*
+* @class Factory
+* @constructor
+*/
+export class Factory {}