[Feature] Update library documentation (#580)

* Minor IHardware doc fixes

* Add XML with documentation to NuGet and output

* Update Software namespace docs

* Update some internal classes

* Update main Computer class docs

* Update interfaces docs

* Update Computer class documentation

* Update motherboard docs

* Update hardware docs

* Fix code formatting

* Update SensorVisitor handler doc

LibreHardwareMonitorLib/Software/OperatingSystem.cs

@@ -8,8 +8,14 @@ using System;
 
 namespace LibreHardwareMonitor.Software
 {
+    /// <summary>
+    /// Contains basic information about the operating system.
+    /// </summary>
     public static class OperatingSystem
     {
+        /// <summary>
+        /// Statically checks if the current system <see cref="Is64Bit"/> and <see cref="IsUnix"/>.
+        /// </summary>
         static OperatingSystem()
         {
             // The operating system doesn't change during execution so let's query it just one time.
@@ -20,8 +26,14 @@ namespace LibreHardwareMonitor.Software
                 Is64Bit = true;
         }
 
+        /// <summary>
+        /// Gets information about whether the current system is 64 bit.
+        /// </summary>
         public static bool Is64Bit { get; }
 
+        /// <summary>
+        /// Gets information about whether the current system is Unix based.
+        /// </summary>
         public static bool IsUnix { get; }
     }
 }