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/Views/Account/Unregister.aspx

@@ -7,5 +7,6 @@ Warning: This will delete all of your data here, your profile, your posts and ot
    <label for="confirmed">Unregister</label> 
    <%=Html.CheckBox("confirmed")%>
    <input type="submit"/>
+   <%= Html.Hidden("UserName") %>
    <% } %>
 </asp:Content>