AUP3: First go at the AUP importer

Near as I can tell, it's pretty much done. Feeding all manner of
.aup projects will definitely need to be done. It would be best
to feed it REAL projects, not the contrived ones I've been playing
with.

src/CMakeLists.txt

@@ -619,7 +619,7 @@ list( APPEND SOURCES
 
       # Standard importers
 
-#      import/ImportAUP.cpp
+      import/ImportAUP.cpp
       import/ImportLOF.cpp
       import/ImportPCM.cpp
       import/ImportPlugin.h

src/ProjectFileManager.cpp

@@ -1193,6 +1193,16 @@ bool ProjectFileManager::Import(
       return false;
    }
 
+   // for AUP ("legacy project") files, do not import the file as if it
+   // were an audio file itself
+   if (fileName.AfterLast('.').IsSameAs(wxT("aup"), false)) {
+      auto &history = ProjectHistory::Get( project );
+
+      history.PushState(XO("Imported '%s'").Format( fileName ), XO("Import"));
+
+      return false;
+   }
+
    // PRL: Undo history is incremented inside this:
    auto newSharedTracks = AddImportedTracks(fileName, std::move(newTracks));
 

src/import/Import.cpp

@@ -15,7 +15,7 @@
   and return the tracks that were imported.  This function just
   figures out which one to call; the actual importers are in
   ImportPCM, ImportMP3, ImportOGG, ImportRawData, ImportLOF,
-  ImportQT and ImportFLAC.
+  ImportQT, ImportFLAC and ImportAUP.
 
 *//***************************************************************//**
 
@@ -29,7 +29,7 @@ It's defined in Import.h
 \class Importer
 \brief Class which actually imports the auido, using functions defined
 in ImportPCM.cpp, ImportMP3.cpp, ImportOGG.cpp, ImportRawData.cpp,
-and ImportLOF.cpp.
+ImportLOF.cpp, and ImportAUP.cpp.
 
 *//******************************************************************/
 
@@ -137,7 +137,7 @@ bool Importer::Initialize()
    using namespace Registry;
    static OrderingPreferenceInitializer init{
       PathStart,
-      { {wxT(""), wxT("PCM,OGG,FLAC,MP3,LOF,FFmpeg") } }
+      { {wxT(""), wxT("AUP,PCM,OGG,FLAC,MP3,LOF,FFmpeg") } }
       // QT and GStreamer are only conditionally compiled and would get
       // placed at the end if present
    };
@@ -634,6 +634,12 @@ bool Importer::Import( AudacityProject &project,
                return true;
             }
 
+            // AUP ("legacy projects") have different semantics
+            if (extension.IsSameAs(wxT("aup"), false))
+            {
+               return true;
+            }
+
             auto end = tracks.end();
             auto iter = std::remove_if( tracks.begin(), end,
                std::mem_fn( &NewChannelGroup::empty ) );