deprecate \schwarzkopf and solve the problem with layers

basic_format_and_style_settings.ly

@@ -61,6 +61,11 @@ generalLayout = \layout {
     \Voice
     % ich will lines breaken wie ich will!
     \remove "Forbid_line_break_engraver"
+    \override NoteHead.layer = 2
+    \override Dots.layer = 2
+    \override Stem.layer = 2
+    \override Flag.layer = 2
+    \override Beam.layer = 2
   }
 }
 
@@ -76,6 +81,11 @@ secondVoiceStyle = {
   \override Stem.color = #grey
   \override Flag.color = #grey
   \override Beam.color = #grey
+  \override NoteHead.layer = 1
+  \override Dots.layer = 1
+  \override Stem.layer = 1
+  \override Flag.layer = 1
+  \override Beam.layer = 1
 }
 
 firstVoiceStyle = {
@@ -86,14 +96,10 @@ firstVoiceStyle = {
   \override Beam.color = #black
 }
 
-% einzelne Noten innerhalb von \secondVoiceStyle mit schwarzem statt grauem Kopf
+% Deprecated: einzelne Noten innerhalb von \secondVoiceStyle mit schwarzem statt grauem Kopf
 schwarzkopf =
   #(define-music-function (parser location noten) (ly:music?)
-  #{
+    (begin (ly:warning "\\schwarzkopf brauchts nicht mehr, das kann ersatzlos weg!") noten))
-   \revert NoteHead.color
-   $noten
-   \override NoteHead.color = #grey
-  #})
 
 romanStanza =
   #(define-music-function (parser location) ()