fix "make headercheck"
includes--
fix spring only listing the default openal device
PE: fix typo found by GF
reduce VA count again (discard GL4 streambuffer idea - it's slower)
PF: nlc equalize varNames between PE & PF (so they can in future share a single interface)
addendum
Merge branch 'develop' into PathUpdateConfig
made "Duplicate AI Interface Info found" an error message:

because this mostly causes a crash!
equalize PE & PF further
fix "use before set"
Fix conflict with PathEstimator.cpp