Found another copy in renderer/Cinematic.cpp. Move the
newer implementation from renderer/Image_files.cpp in its
own file and use the libjpeg v8c license blob (which is where
this code comes from).
Adapt README too with the v8c license.
Don't include the lazy precompiled.h everywhere, only what's
required for the compilation unit.
platform.h needs to be included instead to provide all essential
defines and types.
All includes use the relative path to the neo or the game
specific root.
Move all idlib related includes from idlib/Lib.h to precompiled.h.
precompiled.h still exists for the MFC stuff in tools/.
Add some missing header guards.
The unused WriteLossless() was using libjpeg internals found in
jpegint.h. This header is available with libjpeg8, but not shipped
by most distros. Disable the relevant code - no functional
changes.
