this avoid breaking the game DLL ABI (framework/DeclParticle.h is part
of the SDK), and for now doesn't make a difference, because that keyword
was introduced by TDM and thus is only used in their particle defs.
When we break the game ABI/API anyway (probably for high FPS support),
this commit can just be reverted
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.
