Add new macro: transposition

This macro depends on the repeatedchord environment:
 - if chords are repeated, acts like the \transpose macro from LaTeX package
 - if not, a muscinote information box is displayed with the number of half-steps for transposition

This macro can prove usefull to hide the complexity of songs that transpose their verses (e.g: Barbara - L'aigle noir): in repeatedchords mode, the chords are explicitly displayed (in their transposed form), in norepeatedchords mode, it only provides the information that the verses should be transposed.

tex/crepbook.cls

@@ -70,6 +70,7 @@
 \RequirePackage{tikz}
 \RequirePackage{licence}
 \RequirePackage{xstring}
+\RequirePackage{ifthen}
 
 \iflyric%
   \tabsfalse%
@@ -522,4 +523,18 @@
     \fi%
   }
 \fi
+
+\def\removefirstch@r#1{}
+\newcommand{\transposition}[1]{%
+  \ifnorepeatchords%
+    \musicnote{%
+      \IfStrEq{\@lang}{english}{transposition:~}{}%
+      \IfStrEq{\@lang}{french}{transposition~:~}{}%
+      \ifthenelse{#1>0}{#1$\Uparrow$}{\removefirstch@r#1$\Downarrow$}%
+    }%
+  \else%
+    \transpose{#1}
+  \fi%
+}%
+
 \makeatother