Moved Pass.cs to the Passes folder.

src/Generator/Passes/Pass.cs

@@ -17,6 +17,14 @@ namespace Cxxi.Passes
             return false;
         }
 
+        /// <summary>
+        /// Processes a translation unit.
+        /// </summary>
+        public virtual bool ProcessUnit(TranslationUnit unit)
+        {
+            return false;
+        }
+
         /// <summary>
         /// Processes a declaration.
         /// </summary>