First attempt at new accidentals in git

[Rune Zedeler]

I have put the first attempt at moving accidentals to scheme in dev/rune 
branch.
(Please check that VERSION is 2.11.32.rz3 - I have had some git-problems)

* Split pitch into pitchclass and pitch - pitchclass not containing 
octave information.
Han-Wen please comment on code. I had some problems with getting guile 
to accept  hierarchical smobs.

* Moved accidental rules to scheme
Now the user can write his own accidental rules in the .ly if he is not 
satisfied with the existing ones.

If one for instance should wish to add a cautionary accidental at the 
start of each measure (hmm), then one may do like this:

%%% BEGIN
\version "2.11.32"

#(define (start-of-measure-acc-rule context pitch barnum measurepos)
  (cons #f (equal? measurepos (ly:make-moment 0 1))))

mus = {
  \key des \major
  \transpose c c' {
    g16 g g g' g' d' d' d' g' g' f f gis gis g g' ges1
  }
}
<<
  \new Staff {
    \set Staff.autoCautionaries = #(list 'Staff start-of-measure-acc-rule)
    \relative c' { c4 d e f g gis a ais b2 c }
  }
>>
%%% END

* Added accidental-rules 'neo-modern and 'neo-modern-cautionary - adding 
even more accidentals to the modern accidentals. Notes different from 
the key signature now always gets an accidental if they do not directly 
follow a note of the same pitch.

* Added accidental-rule 'dodecaphonic - thereby obsoleting 
http://lsr.dsi.unimi.it/LSR/Item?id=314 :-)

TODO:

* convert-ly? I don't think this is nessesary. The change is 
downwards-compatible as long as the .ly do not mess around with 
'autoAccidentals and 'autoCautionaries directly. Perhaps we could add a 
simple warning if these properties are accessed.

* Make better use of pitchclass. Currently it is only used in the 
key-signature.

* Some fixme's still in the code. Primarily regarding garbagecollection. 
 Currently it probably leaks like mad.

* Bugtesting, bugtesting, bugtesting.

-Rune