Improves notification system

* ICalendarManager.cs: WIP booking TODO a calendar provider

* NpgsqlProfileProvider.cs: Fixes the defaultValue specification from
  config file

* BlogsController.cs:
* AccountController.cs:
* CalendarController.cs: refactoring : the Yavsc controller name

* instdbws.sql: a new profile value : a boolean, `AllowCookies` :'{

* style.css: a class to display notification

* HomeController.cs: Notifies users this site uses cookies (what for
  an information!)
If authenticated, at dimissing this notification, the user's profile
  is updated,
and he'll not mess up anymore with the info.

* App.master:
* YavscHelpers.cs: adds usage of click_action value at
displaying a notification.

* yavsc.js: Implements the notification `click_action`

* Web.config: * enables anonymous profiles
* adds a new `allowcookies` profile property

* Web.csproj: Yavsc controller refactoring

* YaEvent.cs:
* IFreeDateSet.cs: WIP booking

* LocalizedText.resx:
* LocalizedText.fr.resx:
* LocalizedText.Designer.cs:
* LocalizedText.fr.Designer.cs: implements the message "uses cookies"

* YavscModel.csproj: refactoring

* Notification.cs: The Yavsc otification will start as a Google one
  ...
many properties are not yet used, but all seems usefull.

* Web.config: code prettying

* YavscController.cs: Gives Yavsc a concrete base controller

web/App_Themes/style.css

@@ -27,6 +27,16 @@ body {
                 url('/images/FhHRx.gif') 
                 50% 50% 
                 no-repeat;
+    overflow:   scroll; 
+}
+.dispmodal {
+    position:   fixed;
+    z-index:    1000;
+    top:        0;
+    left:       0;
+    height:     100%;
+    width:      100%;
+    overflow:   scroll; 
 }
 
 body.loading {
@@ -217,6 +227,10 @@ label {
 	font-size: large;
 	background-color: rgba(64,64,0,0.5);
 	border: solid green 1px;
+	padding: 1em;
+	border-radius:1em;
+	margin:1em;
+	padding:1em;
 	}
 .dirty { 
 	background-color: rgba(128,128,0,0.5);
@@ -356,6 +370,9 @@ header h1, header a , .actionlink, .menuitem, a { padding:.5em;}
   }
   #notifications { 
 	padding: .5em;
+	border-radius:.5em;
+	margin:.5em;
+	padding:.5em;
  }
 	.menuitem {
 		display: block;