ifilter fix

        internal static IFilter LoadAndInitIFilter(string fileName, string extension)
        {
            IFilter filter = LoadIFilter(extension);

            if (filter == null)
                return null;

            var iPersistStream = filter as IPersistStream;
            if (iPersistStream != null)
            {
                IFILTER_FLAGS flags;
                IFILTER_INIT iflags =
                            IFILTER_INIT.CANON_HYPHENS |
                            IFILTER_INIT.CANON_PARAGRAPHS |
                            IFILTER_INIT.CANON_SPACES |
                            IFILTER_INIT.APPLY_INDEX_ATTRIBUTES |
                            IFILTER_INIT.HARD_LINE_BREAKS |
                            IFILTER_INIT.FILTER_OWNED_VALUE_OK;

                Stream fileStream = new System.IO.FileStream(fileName, FileMode.Open);
                StreamWrapper wrapper = new StreamWrapper(fileStream);
                iPersistStream.Load(wrapper);

                if (filter.Init(iflags, 0, IntPtr.Zero, out flags) == IFilterReturnCode.S_OK)
                    return filter;
            }

            IPersistFile persistFile = (filter as IPersistFile);
            if (persistFile != null)
            {
                persistFile.Load(fileName, 0);
                IFILTER_FLAGS flags;
                IFILTER_INIT iflags =
                            IFILTER_INIT.CANON_HYPHENS |
                            IFILTER_INIT.CANON_PARAGRAPHS |
                            IFILTER_INIT.CANON_SPACES |
                            IFILTER_INIT.APPLY_INDEX_ATTRIBUTES |
                            IFILTER_INIT.HARD_LINE_BREAKS |
                            IFILTER_INIT.FILTER_OWNED_VALUE_OK;

                if (filter.Init(iflags, 0, IntPtr.Zero, out flags) == IFilterReturnCode.S_OK)
                    return filter;
            }
            //If we failed to retreive an IPersistFile interface or to initialize
            //the filter, we release it and return null.
            Marshal.ReleaseComObject(filter);
            return null;
        }