add renaming and sctable funs
change to newer macro escape mechanism, using uints in more places
comments & whitespace
parser comments
removed obsolete reference to purity
rename repr to name
just use TLS interner
removed some interner fields
interner just uses uints, not idents with syntax context
token_to_ident takes argument by reference
remove unused cx's
rand example fixup
remove interner from tt_reader
remove interner field from string_reader
removed unused imports (and one unused argument)
remove unused get_ident_interner's
add hygiene support functions
added fresh-name fn
moved TLS of sctable to ast_util, hid parameter in hygiene calls