this test passes nowadays
start introducing string strategies
make Symbols store unicode
minimal support for immutable strings
progress
make sure getitem returns a unicode char
fix a few more uses of symbol

(of course that code is untested)
rudimentary implementation of upper and lower

only for ascii so far
reinstate make

make checks whether a literal is all ascii
test and fix the string->*-symbol variants
string->immutable-string, test and fix
start having some support for mutable unicode strings
fix format
don't use as_str_ascii here
__init__ first, newlines
always check whether a utf-8 encoded string is all ascii
test and fix for unicode in read-line and open-input-string
independent of locale, always encode using utf-8
read-char unicode support
upcase and downcase of unicode strings