[PATCH] Allow \markuplines to be assigned to a variable

[Reinhold Kainhofer]

Here's a patch that allows markup lines to be assigned to a variable:
http://codereview.appspot.com/3855043

So far, the following was invalid syntax:

mytext = \markuplines {
  \justified-lines { Lorem ipsum dolor sit amet, ...  } }

\markuplines \mytext

Okay to push?

Cheers,
Reinhold
-- 
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Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org