Moving corlib files out of "System" directory into root

BeefLibs/corlib/src/IRefCounted.bf

@@ -0,0 +1,57 @@
+using System.Threading;
+using System.Diagnostics;
+
+namespace System
+{
+	interface IRefCounted
+	{
+		void AddRef();
+		void ReleaseRef();
+	}
+
+	class RefCounted : IRefCounted
+	{
+		protected int32 mRefCount = 1;
+
+		public ~this()
+		{
+			Debug.Assert(mRefCount == 0);
+		}
+
+		public int RefCount
+		{
+			get
+			{
+				return mRefCount;
+			}
+		}
+
+		public void DeleteUnchecked()
+		{
+			mRefCount = 0;
+			delete this;
+		}
+
+		public void AddRef()
+		{
+			Interlocked.Increment(ref mRefCount);
+		}
+
+		public void ReleaseRef()
+		{
+			int refCount = Interlocked.Decrement(ref mRefCount);
+			Debug.Assert(refCount >= 0);
+			if (refCount == 0)
+			{
+				delete this;
+			}
+		}
+
+		public int ReleaseRefNoDelete()
+		{
+			int refCount = Interlocked.Decrement(ref mRefCount);
+			Debug.Assert(refCount >= 0);
+			return refCount;
+		}
+	}
+}