Fixed 4979 (Doesn't allow any ordering of int modifiers)
Fixed and cleaned up Token::Match engine
Reduced Token::Match complexity, better support for complex patterns
Fixed two issues in matchcompiler:
- Use correct findmatch or findsimplematch for verification
- Print failing pattern also for findmatch/findsimplematch
travis: replace kernel check with clang check.

Check clang instead of kernel, which is a lot faster.
Make clang check failure fatal to the build.
travis: add -DCHECK_INTERNAL to the VERIFY=1 job to automatically fetch issues like #5869 via travis, check clang with --exception-handling
travis: make clang check sensitive to internal cppcheck errors.