Fix segfault from orphaned-lines code

Patch set 1 comes from http://codereview.appspot.com/4236047/
Patch set 2 applies the suggestions made there

[Graham Percival (old account), 2011-03-07 13:12:32]

LGTM, and thanks so much for working on this!

http://codereview.appspot.com/4253061/diff/2001/input/regression/markup-lines.ly
File input/regression/markup-lines.ly (right):

http://codereview.appspot.com/4253061/diff/2001/input/regression/markup-lines...
input/regression/markup-lines.ly:1: \version "2.12.0"
Doesn't really matter, but could this be bumped to 2.13.53 to reflect that the
file (as modified) won't compile in an earlier version?

[Neil Puttock, 2011-03-07 22:21:22]

Hi Keith,

LGTM.

Can you put a \book { } block around all the \markuplines so we can see the page
numbers?

Cheers,
Neil

http://codereview.appspot.com/4253061/diff/2001/input/regression/markup-lines.ly
File input/regression/markup-lines.ly (right):

http://codereview.appspot.com/4253061/diff/2001/input/regression/markup-lines...
input/regression/markup-lines.ly:34: } \markuplines \override-lines
#'(baseline-skip . 3.9) {
newline for each \markuplines

http://codereview.appspot.com/4253061/diff/2001/lily/paper-book.cc
File lily/paper-book.cc (right):

http://codereview.appspot.com/4253061/diff/2001/lily/paper-book.cc#newcode521
lily/paper-book.cc:521: for (SCM list = texts ; scm_is_pair (list) ; list =
scm_cdr (list))
(SCM list = texts; scm_is_pair (list); list = scm_cdr (list))

http://codereview.appspot.com/4253061/diff/2001/lily/paper-book.cc#newcode558
lily/paper-book.cc:558: /*
fix indent (+ next two lines)

http://codereview.appspot.com/4253061/diff/2001/lily/paper-book.cc#newcode564
lily/paper-book.cc:564: first->set_property ("first-markup-line", SCM_BOOL_T);
fix indent (+ next line)

[Keith, 2011-03-08 03:05:08]

On 2011/03/07 22:21:22, Neil Puttock wrote:
> 
> LGTM.
> 
> Can you put a \book { } block around all the \markuplines so we can 
> see the page numbers?

... for when the reg-test is processed by lilypond-book to make the HTML page of
all regression tests.  Got it.

Patch set 3 incorporates the suggestions above this message.

[Graham Percival (old account), 2011-03-10 12:08:29]

Ok, time's over with no objections.  Could you please push this?