Added the ability to remove a built-in pass.

src/Generator/Passes/PassBuilder.cs

@@ -32,6 +32,14 @@ namespace CppSharp
             Passes.Add(pass);
         }
 
+        /// <summary>
+        /// Remove a previously-added pass, if exists.
+        /// </summary>
+        public bool RemovePass(T pass)
+        {
+            return pass is TranslationUnitPass && Passes.Remove(pass);
+        }
+
         /// <summary>
         /// Finds a previously-added pass of the given type.
         /// </summary>