First attempt at porting the EAX reverb code to EFX.
This only works when the ALC_EXT_EFX extension is supported by
the OpenAL vendor (which is not the case for the OSX supplied
framework, use OpenAL soft instead).
The current stable version of OpenAL Soft (v1.13 as of this
writing) can barely handle this additional workload, current
master is highly recommended when using this feature.
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.
