merge this with earlier
removed unused imports (and one unused argument)
working on let-hygiene
added fresh-name fn
moved TLS of sctable to ast_util, hid parameter in hygiene calls
starting to add sexp encoder
tmp
tmp
tmp -- but compiles!
tmp
tmp
tmp
expansion now covers macros, test cases for renaming
removed unneccessary SyntaxExpander structs
separate ItemDecorator from ItemDecorator
refactor so tt_fold only requires an ident->ident fn
adding test case to check marking/unmarking
comment
comment
comment