* Mother of all commits:

* Cleaned up copyright notices in AssemblyInfo.cs's
* Added Copyright headers to a bunch of files missing them
* Replaced several common string instances with a static constant to prevent reallocation of the same strings thousands of times. "" -> String.Empty is the first such candidate.

OpenSim/Region/Environment/Scenes/Scripting/NullScriptHost.cs

@@ -44,19 +44,19 @@ namespace OpenSim.Region.Environment.Scenes.Scripting
 
         public string SitName
         {
-            get { return ""; }
+            get { return String.Empty; }
             set { }
         }
 
         public string TouchName
         {
-            get { return ""; }
+            get { return String.Empty; }
             set { }
         }
 
         public string Description
         {
-            get { return ""; }
+            get { return String.Empty; }
             set { }
         }