This is the last parameter for A_RadiusThrust() DECORATE function.
If it is omitted or none, then A_RadiusThrust will behave as usual.
If it is set for some species name, it witt thrust only that species.
Of course, these species should be +VULNERABLE to be thrustable.
There are two options here - one only disables the vertical thrust and the other goes back fully to the original non-z-aware code.
Both options are settable through MAPINFO.
For the compatibility presets, the normal ones only disable the vertical thrust, the strict ones force use of the old code entirely.
