Adds a warning for non-list fingeringOrientations settings. (issue4650070)

[mtsolo]

Reviewers: ,

Message:
Fixes issue 1734.

Description:
Adds a warning for non-list fingeringOrientations settings.

Please review this at http://codereview.appspot.com/4650070/

Affected files:
  M lily/new-fingering-engraver.cc


Index: lily/new-fingering-engraver.cc
diff --git a/lily/new-fingering-engraver.cc b/lily/new-fingering-engraver.cc
index  
db99dede95b2979324c3d7858911928bb67ac069..9909790b1d72e0c368f91837c078c4e6af4029bf  
100644
--- a/lily/new-fingering-engraver.cc
+++ b/lily/new-fingering-engraver.cc
@@ -178,6 +178,11 @@ void
 New_fingering_engraver::position_scripts (SCM orientations,
                                          vector<Finger_tuple> *scripts)
 {
+  if (scm_list_p (orientations) != SCM_BOOL_T)
+    {
+      warning ("fingeringOrientations must be a list.  Setting to '(up  
down).");
+      orientations = scm_list_2 (ly_symbol2scm ("up"), ly_symbol2scm  
("down"));
+    }
   for (vsize i = 0; i < scripts->size (); i++)
     if (stem_ && to_boolean (scripts->at (i).script_->get_property  
("add-stem-support")))
       Side_position_interface::add_support (scripts->at (i).script_,  
stem_);