Initial XEX support (#77)

* Initial XEX support

* Fix build

* Fix reader

* Fix reader, again

* Rename field to CertificateOffset

* Update reader

* Update Printer

* Update Printer

* Parse Certificate

* More info

* Fix build

SabreTools.Data.Models/XenonExecutable/Executable.cs

@@ -0,0 +1,31 @@
+namespace SabreTools.Data.Models.XenonExecutable
+{
+    /// <summary>
+    /// Xenon (Xbox 360) Executable format (XEX2)
+    /// It is based on PE format and is PPC architecutre (therefore Big-Endian)
+    /// During alpha stage, Xenon was a slightly modified Apple Power Mac G5
+    /// Early (Before March 2005) builds used pure PE-formatted executables, June 2005 XDK began requiring XEX-format
+    /// Early (August 2005 and earlier) XEX-format images (XEX0, XEX?, XEX-, XEX1) are not supported.
+    /// </summary>
+    /// <see href="http://oskarsapps.mine.nu/xexdump"/>
+    /// <see href="https://free60.org/System-Software/Formats/XEX/"/>
+    public class Executable
+    {
+        /// <summary>
+        /// XEX header
+        /// </summary>
+        public Header Header { get; set; } = new();
+
+        /// <summary>
+        /// XEX certificate structure
+        /// </summary>
+        public Certificate Certificate { get; set; } = new();
+
+        /// <summary>
+        /// PE data, too large to be read into memory
+        /// Encrypted and/or compressed blob on most XEX files
+        /// Occassionally padded with zeroes at the end
+        /// </summary>
+        public byte[]? CompressedData { get; set; }
+    }
+}