Request: Change squish() to allow a trim character

[Hope-Shangrila]

trim() allows special combinations like %r to be specified as the trim character. It would be useful for squish() to allow the same. Right now it accepts a character, but can it be changed to accept %r and other special combinations.

[brazilofmux]

The upper-level function already does the right thing. However, mux_string::compress(UTF8 *ch) would need to support multiple characters. FYI. %r is really CRLF, which is two characters.