Avoid null-pointer exception with old-style third-party hardware folders.

Author: damellis

app/src/processing/app/debug/TargetPlatform.java

@@ -45,6 +45,7 @@ public TargetPlatform(String _name, File _folder) {
     name = _name;
     folder = _folder;
     boards = new HashMap<String, PreferencesMap>();
+    boardsOrder = new ArrayList<String>();
     programmers = new HashMap<String, PreferencesMap>();
     preferences = new PreferencesMap();