Partially add VBSP lump 40

SabreTools.Models/BSP/PakfileLump.cs

@@ -0,0 +1,43 @@
+namespace SabreTools.Models.BSP
+{
+    /// <summary>
+    /// The Pakfile lump (Lump 40) is a special lump that can contains
+    /// multiple files which are embedded into the bsp file. Usually,
+    /// they contain special texture (.vtf) and material (.vmt) files
+    /// which are used to store the reflection maps from env_cubemap
+    /// entities in the map; these files are built and placed in the
+    /// Pakfile lump when the buildcubemaps console command is executed.
+    /// The Pakfile can optionally contain such things as custom textures
+    /// and prop models used in the map, and are placed into the bsp file
+    /// by using the BSPZIP program (or alternate programs such as Pakrat).
+    /// These files are integrated into the game engine's file system
+    /// and will be loaded preferentially before externally located
+    /// files are used.
+    /// 
+    /// The format of the Pakfile lump is identical to that used by the
+    /// Zip compression utility when no compression is specified (i.e.,
+    /// the individual files are stored in uncompressed format). In some
+    /// branches, such as , LZMA compression can be used as well. If the
+    /// Pakfile lump is extracted and written to a file, it can therefore
+    /// be opened with WinZip and similar programs.
+    /// 
+    /// The header public/zip_uncompressed.h defines the structures
+    /// present in the Pakfile lump. The last element in the lump is a
+    /// ZIP_EndOfCentralDirRecord structure. This points to an array of
+    /// ZIP_FileHeader structures immediately preceeding it, one for each
+    /// file present in the Pak. Each of these headers then point to
+    /// ZIP_LocalFileHeader structures that are followed by that file's
+    /// data. 
+    /// 
+    /// The Pakfile lump is usually the last element of the bsp file.
+    /// </summary>
+    /// <see href="https://developer.valvesoftware.com/wiki/BSP_(Source)"/> 
+    public sealed class PakfileLump
+    {
+        /// <summary>
+        /// Pakfile data
+        /// </summary>
+        /// TODO: Split and/or decompress data?
+        public byte[]? Data;
+    }
+}

SabreTools.Models/BSP/VbspFile.cs

@@ -229,8 +229,10 @@ namespace SabreTools.Models.BSP
         /// TODO: Find definition and implement
         // public PrimIndicesLump? PrimIndicesLump { get; set; }
 
-        // TODO: Implement Lump 40
-        // https://developer.valvesoftware.com/wiki/BSP_(Source)#Pakfile
+        /// <summary>
+        /// LUMP_PAKFILE [40]
+        /// </summary>
+        public PakfileLump? PakfileLump { get; set; }
 
         /// <summary>
         /// LUMP_CLIPPORTALVERTS [41]