[PATCH] Fix issues #1259 and #1433 (\breakDynamicSpan and a spanner's style=#'none over a line break)

[Reinhold Kainhofer]

Finally, I found a way to fix issues #1259 and #1433. Patch is up at:
http://codereview.appspot.com/4630070

Please review!

Fix  issues 1259 and 1433 (\breakDynamicSpan and a spanner's style=#'none over 
a line break)

With \breakDynamicSpan and \override DynamicTextSpanner #'style = #'none
the DynamicLineSpanner will be artificially shortened to allow independent
vertical alignment. In these cases, the dynamic spanners will no longer
be fully contained in their parent DynamicLineSpanner.

The Spanner::do_break_processing() function, however, checks if the
spanner is fully contained in its parent. The above cases are valid
cases where this is violated, so an exception is added to that check.

The only way to achieve this is to set a property (parent-spanner-shortened)
for all children of the shortened DynamicLineSpanner. The
Spanner::do_break_processing function then can simply check
for this property and allow all spanners with that property to span
more than the parent spanner.

This fixes both issues 1259 and 1433:
http://code.google.com/p/lilypond/issues/detail?id=1259
http://code.google.com/p/lilypond/issues/detail?id=1433

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