librustc: Lots of de-muting. rs=demuting
libsyntax: De-mut TtFrame
libsyntax: Use more @self in diagnostics
libsyntax: De-mut the handler and span handler
libsyntax: De-mut TtReader and StringReader
libsyntax: De-mut the pretty printer
libsyntax: De-mut ext ctxt
libsyntax: De-mut the AST map
librustc: De-mut regionck.
librustc: De-mut the borrow check
librustc: De-mut some trans modules
librustc: Update for write barriers and de-mut region inference
librustc: De-mut region.rs
librustc: De-mut writeback
librustc: De-mut infer and infer/resolve