Changing shell settings loader to prep for multi-tenancy work

Adding data prefix property
Moving to a different yaml library
Renaming IShellSettingsLoader and ShellSettingsLoader to ITenantManager and DefaultTenantManager
Avoiding use of MapPath in the appdatafolder abstraction

--HG--
branch : dev

lib/yaml/Readme.txt

@@ -0,0 +1,39 @@
+YamlSerializer 0.9.0.2 (2009-10-04)        Osamu TAKEUCHI <osamu@big.jp>
+
+Description:
+	A library that serialize / deserialize C# native objects into YAML1.2 text.
+
+Development environment: 
+	Visual C# 2008 Express Edition
+	Sandcastle (2008-05-29)
+	SandcastleBuilder 1.8.0.2
+	HTML Help workshop 4.74.8702
+	NUnit 2.5.0.9122
+	TestDriven.NET 2.0
+
+Support web page: 
+	http://yamlserializer.codeplex.com/
+
+License:
+	YamlSerializer is distributed under the MIT license as following:
+
+---
+The MIT License (MIT)
+Copyright (c) 2009 Osamu TAKEUCHI <osamu@big.jp>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of 
+this software and associated documentation files (the "Software"), to deal in the 
+Software without restriction, including without limitation the rights to use, copy, 
+modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, 
+and to permit persons to whom the Software is furnished to do so, subject to the 
+following conditions:
+
+The above copyright notice and this permission notice shall be included in all 
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
+CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
+OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.