Fix build with latest clang
Simplify unit tests by letting cmake generate code in the simple case
Print stack trace on error also in tests
Fix assertion in clang::Lexer::isAt[End/Start]OfMacroExpansion()

Apparently this can now only be called if SourceLocation.isMacroID()
returns true
update README
FindClang: fix CLANG_LIBRARY_DIR
Add the directory of the clang builtin includes to the search path

Currently only for the tests, will have to figure out how to do that
for the main executable as well
Remove useless message