Perl module to quote strings suitably for RFC2822 local parts

 Convert::YText converts strings to and from "YText", a format inspired by
 xtext defined in RFC1894, the MIME base64 and quoted-printable types (RFC
 1394). The main goal is encode a UTF8 string into something safe for use as
 the local part in an internet email address (RFC2822).
 .
 By default spaces are replaced with "+", "/" with "~", the characters
 "A-Za-z0-9_.-" encode as themselves, and everything else is written "=USTR="
 where USTR is the base64 (using "A-Za-z0-9_." as digits) encoding of the
 unicode character code. The encoding is configurable (see below).