Further header & precompiled cleanup, fix no-PCH builds.

GUIObjectBase is made a IGUIObject* to avoid including those headers
un-necessarily. Subsequent diffs ought to clean up the various of
pointers for that with a similar type with reference semantics.

Also:
- Add standard C and C++ headers (mostly cstring for memcpy, string and
vector) where needed.
- Swap out some includes for forward declarations
- Clean up un-necessary boost includes in precompiled and other headers.
- Clean up precompiled headers, including fewer things.
- Move ACPI to the windows-specific folder as it's included there only
and mostly specific to that platform.

Thanks Stan for the testing.

Differential Revision: https://code.wildfiregames.com/D3129
This was SVN commit r24352.

source/lib/regex.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2010 Wildfire Games.
+/* Copyright (C) 2020 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -24,6 +24,7 @@
 
 #include "precompiled.h"
 
+#include <cwctype>
 
 int match_wildcard(const wchar_t* s, const wchar_t* w)
 {