Headers: Use shortcomposer; fix footer

orchestrallily.ily

@@ -1561,7 +1561,7 @@ setCopyrightPages = #(define-music-function (parser location pages) (list?)
   }
   olyInstrumentEvenHeaderMarkup = \markup \fill-line {
     \on-the-fly #is-header-page \fromproperty #'page:page-number-string
-    \on-the-fly #is-header-page \concat { \fromproperty #'header:composer ": " \fromproperty #'header:title }
+    \on-the-fly #is-header-page \concat { \fromproperty #'header:shortcomposer ": " \fromproperty #'header:title }
     " "
   }
   oddHeaderMarkup = \olyStdOddHeaderMarkup
@@ -1598,6 +1598,7 @@ setCopyrightPages = #(define-music-function (parser location pages) (list?)
     }
   }
   oddFooterMarkup = \olyStdOddFooterMarkup
+  evenFooterMarkup = \olyStdOddFooterMarkup
 }