Working towards definition import/export

Reader and writer mapping definition to infoset
Devtools placeholder providing way to see/alter metadata
Reader on builder over existing content definition provides merge capabilies on import

--HG--
branch : dev

src/Orchard.Web/Modules/Orchard.Users/Controllers/AdminController.cs

@@ -10,6 +10,7 @@ using Orchard.Users.Services;
 using Orchard.Users.ViewModels;
 
 namespace Orchard.Users.Controllers {
+    [ValidateInput(false)]
     public class AdminController : Controller, IUpdateModel {
         private readonly IMembershipService _membershipService;
         private readonly IUserService _userService;