[O] Bug: text export and multi-word link descriptions with line breaks

[Mathias Bauer]

Dear Maintainers,

I just stumbled over Org's plain text export and how it works on
links with descriptions consisting of multiple words and line
breaks between them.  I'm running Org stable version 8.2.5h.

Org source (spaces at the end of line 1 and 2 don't matter):

--------------------snip--------------------
"OpenPGP Message Format" ([[https://tools.ietf.org/html/rfc4880][RFC
4880]] which obsoletes [[https://tools.ietf.org/html/rfc1991][RFC
1991]] and [[https://tools.ietf.org/html/rfc2440][RFC 2440]])...
...
foo [[https://tools.ietf.org/html/rfc4880][RFC 4880]] bar
baz [[https://tools.ietf.org/html/rfc1991][RFC 1991]] foo
bar [[https://tools.ietf.org/html/rfc2440][RFC 2440]] baz
--------------------snip--------------------

Text export result:

--------------------snip--------------------
"OpenPGP Message Format" ([RFC 4880] which obsoletes [RFC 1991] and [RFC
2440])...  ...  foo [RFC 4880] bar baz [RFC 1991] foo bar [RFC 2440] baz


[RFC 4880] https://tools.ietf.org/html/rfc4880

[RFC 1991] https://tools.ietf.org/html/rfc1991

[RFC 2440] https://tools.ietf.org/html/rfc2440

[RFC 4880] https://tools.ietf.org/html/rfc4880

[RFC 1991] https://tools.ietf.org/html/rfc1991
--------------------snip--------------------

These multiple references look quite bad.  Is it possible to
"normalize" the descriptions in some way *before* checking them
for uniqueness and output them thereafter?

Thanks for considering this issue.

Kind regards
Mathias