Big code import from bfbbs repo. bfbbdecomp#1

A lot of code ported into xWad4 and xWad2 and ZWadUI. All compiler warnings fixed.

Author: LivewireCB

.vscode/settings.json

@@ -16,7 +16,8 @@
   "files.trimFinalNewlines": true,
   "files.associations": {
     "*.inc": "c",
-    ".clangd": "yaml"
+    ".clangd": "yaml",
+    "cstring": "cpp"
   },
   // Disable C/C++ IntelliSense, use clangd instead
   "C_Cpp.intelliSenseEngine": "default",