outline of Case::MappedString
Case::MappedString working run
add |rfc1459| infix operator
as_upper / as_lower
document infix casemap cmp operator
MappedString as_upper/as_lower produce MappedStrings
t/; test MappedString methods
Merge branch 'cmap-overload'

* cmap-overload:
  t/; test MappedString methods
  MappedString as_upper/as_lower produce MappedStrings
  document infix casemap cmp operator
  as_upper / as_lower
  add |rfc1459| infix operator
  Case::MappedString working run
  outline of Case::MappedString