Make Import the default action in the Import Dialog

Double clicking on a file or pressing the Return key will now import it.

This means with autoplay enabled you can navigate a directory of audio files
using the up and down arrow keys and import the wanted files (with Return)
without having to touch the mouse.

Being able to use double click to import a file means you don't have to move
the mouse back and forth between the file browser and the import button.

You can still manually audition the file with space as before.

gtk2_ardour/sfdb_ui.cc

@@ -819,6 +819,12 @@ SoundFileBrowser::set_action_sensitive (bool yn)
 	import_button.set_sensitive (yn);
 }
 
+bool
+SoundFileBrowser::get_action_sensitive () const
+{
+	return import_button.get_sensitive ();
+}
+
 void
 SoundFileBrowser::do_something (int action)
 {
@@ -840,6 +846,12 @@ SoundFileBrowser::on_key_press_event (GdkEventKey* ev)
 		do_something (RESPONSE_CLOSE);
 		return true;
 	}
+	if (ev->keyval == GDK_space && ev->type == GDK_KEY_PRESS) {
+		if (get_action_sensitive()) {
+			preview.audition();
+			return true;
+		}
+	}
 	return ArdourWindow::on_key_press_event (ev);
 }
 
@@ -853,7 +865,7 @@ SoundFileBrowser::clear_selection ()
 void
 SoundFileBrowser::chooser_file_activated ()
 {
-	preview.audition ();
+	do_something (RESPONSE_OK);
 }
 
 void

gtk2_ardour/sfdb_ui.h

@@ -249,6 +249,7 @@ class SoundFileBrowser : public ArdourWindow
 	bool on_audio_and_midi_filter (const Gtk::FileFilter::Info& filter_info);
 
 	void set_action_sensitive (bool);
+	bool get_action_sensitive () const;
 
 	virtual bool reset_options () { return true; }