TZUTCINFO kludge lines, if present.
Now exports a TZUTC kludge line (with time zone format specified in FSP-1001).

export_echomail() now automatically generates MSGID, REPLY, and PID kludge
lines or uses the originals if they exist; FLAGS and unrecognized kludge lines
are also added to exported messages.

already listed.

- hopefully eliminates FAQs about this file.
Changed attachment() function to use enum values for "mode" instead of cryptic
"cleanup" constants (0, 1, and 2).

Removed the CVS revision from the tear line.

(used to always do this, but some non-conforming echomail programs apparently
treat sole-carriage returns as soft-CRs and ignore/strip them).

Changed tag line (removed "Synchronet+" and added platform description).

Switched from fsopen to fnopen.

return value (some implementations do not return negative on overflow).