Add Staff.midiCC context property, refactor handling of MIDI control changes

lily/include/audio-item.hh

 /*
   This file is part of LilyPond, the GNU music typesetter.
 
   Copyright (C) 1996--2015 Jan Nieuwenhuizen <janneke@gnu.org>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
@@ skipping 120 matching lines @@
 
 class Audio_time_signature : public Audio_item
 {
 public:
   Audio_time_signature (int beats, int one_beat);
 
   int beats_;
   int one_beat_;
 };
 
-class Audio_control_function_value_change : public Audio_item
+class Audio_control_change : public Audio_item
 {
 public:
-  // Supported control functions.
-  enum Control
-  {
-    BALANCE = 0, PAN_POSITION, EXPRESSION, REVERB_LEVEL, CHORUS_LEVEL,
-    // pseudo value for representing the size of the enum; must be kept last
-    NUM_CONTROLS
-  };
+  Audio_control_change (int control, int value);
 
-  Audio_control_function_value_change (Control control, Real value);
-
-  // Information about a context property corresponding to a control function
-  // (name, the corresponding enumeration value, and the allowed range for the
-  // value of the context property).
-  struct Context_property
-  {
-    const char *name_;
-    Control control_;
-    Real range_min_;
-    Real range_max_;
-  };
-
-  // Mapping from supported control functions to the corresponding context
-  // properties.
-  static const Context_property context_properties_[];
-
-  Control control_;
-  Real value_;
+  int control_;
+  int value_;
 };
 
 int moment_to_ticks (Moment);
 Real moment_to_real (Moment);
 Moment remap_grace_duration (Moment);
 
 #endif // AUDIO_ITEM_HH