Add XML comments to public entities.

Aaru.Database/Models/BaseOperatingSystem.cs

@@ -32,11 +32,26 @@
 
 namespace Aaru.Database.Models
 {
+    /// <summary>
+    /// Operating system statistics
+    /// </summary>
     public abstract class BaseOperatingSystem : BaseModel
     {
+        /// <summary>
+        /// Operating system name
+        /// </summary>
         public string Name         { get; set; }
+        /// <summary>
+        /// Operating system version
+        /// </summary>
         public string Version      { get; set; }
+        /// <summary>
+        /// Has already been synchronized with Aaru's server
+        /// </summary>
         public bool   Synchronized { get; set; }
+        /// <summary>
+        /// Statistical count
+        /// </summary>
         public ulong  Count        { get; set; }
     }
 }