Update FNModulePrecooler.cs for more functionality

[attosecond]

Added two forms of update: allow for a single intake/precooler part (via welding or maybe a new original model) by checking if the precooler part itself provides IntakeAir, and allow for 1 degree of separation by checking not only directly attached parts for IntakeAir, but also checking all parts directly attached to the precooler parent part and the precooler's immediate child parts.

[Joeppie]

This sounds like a good idea. I have cannot get precoolers to work with anything other than the stock intakes on the compiled version of the code.