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/App_Themes/style.css

@@ -235,7 +235,6 @@ input, select {
 
 
 .menuitem {
-	background-color: rgba(0,0,40,.8); 
 	border-radius:5px;
 	margin:.5em;
 	padding:.5em;