Starting to test some controller

* BlogUnitTest.cs: Should test the user registration

* NpgsqlBlogProvider.cs: Fixes usage of Npgsql upgrade to latest
  version

* TestAPI.csproj: switch to .Net framework 4.5.1

* AccountController.cs: refactoring password validation

* CalendarController.cs:
* WorkFlowController.cs: SendActivationMessage became an extension
  method

* style.css: menu items already have a background and color, since
  they're `<A>` tags

* Unregister.aspx:
* AccountController.cs: refactoring user registration

* BlogsController.cs: Fixes a confusion between Author and reader ...

* YavscHelpers.cs: refactoring the password reset

* App.master: no more <div class="menuitem">, they're hyperlinks

* Login.aspx:
* Profile.aspx: refactoring the user registration

* BlogEntryCollection.cs: implements a method to filter a given post
  collection in order to be displayed tu a given user or anonymous

web/Models/App.master

@@ -103,11 +103,9 @@ $(document).ready(function(){
 </div>
 </a>
 <% } else { %>
-<a href="/Blog/<%= HttpContext.Current.User.Identity.Name%>" accesskey = "B" >
-<div class="menuitem">
+<a href="/Blog/<%= HttpContext.Current.User.Identity.Name%>" accesskey = "B" class="menuitem">
 <img src="<%=Html.AvatarUrl(HttpContext.Current.User.Identity.Name)%>" alt="vos billets" class="iconsmall" />
 <div class="hint">Vos billets</div>
-</div>
 </a>
 <a href="<%= Url.Content("~/Account/Profile/" + HttpContext.Current.User.Identity.Name) %>" accesskey="L" class="menuitem">
 <i class="fa fa-user"></i> <%= HttpContext.Current.User.Identity.Name %>