RehearsalMark extent shouldn't count

[Bertalan Fodor]

In my opinion rehearsal mark extent shouldn't cause notes' extent to 
grow. It should work as in TextScript:

Bad:
\score {
b8 \mark \markup {\small \bold "Parlando"} as g16 g8.~g4 g16 g8 g16 | 
c16 c c c c c c | c c c c c c c c | c c c c c c c c
}

Good:

\score {
b8^\markup {\small \bold "Parlando"} as g16 g8.~g4 g16 g8 g16 | c16 c c 
c c c c | c c c c c c c c | c c c c c c c c
}

Bert