remove CheckMakePairUsesDeduction

Irrelevant
remove CheckForIncludeWhatYouUse

Only checks C++ related headers
remove CheckCStyleCast
remove CheckForNonConstReference

irrelevant
remove "stream check" from CheckIncludeLine

irrelevant
remove C++ only stuff from CheckLanguage

Do we want VLAs?
remove some unused variables
remove unused function
remove CheckSectionSpacing

irrelevant
remove C++ stuff from CheckSpacing
remove C++ stuff from CheckSpacingForFunctionCall
clean up CheckForNonStandardConstruct

remove C++ stuff and add C types
remove C++ only _NestingState parts
remove CleanseRawStrings
remove cpp file extensions
remove cpp headers
remove some leftover function calls
remove leftover c++ headers
More cleanup
Re-integrate FEAT_FILTERPIPE code