Lexer; subtly wrong; no makefile
Add raw string literal ambiguity document
First pass at line comment correctness
Refine the tooling, handle comments
Byte/raw binary literal fixes
ignore-lexer-test to broken files and remove some tray hyphens

I blame @ChrisMorgan for the hyphens.
lexer tests: makefile/configure
Break apart long lines in verify.rs
Shuffle around check-lexer conditions
Add a ton of ignore-lexer-test
Don't run lexer tests by default
auto merge of #15867 : cmr/rust/rewrite-lexer4, r=alexcrichton