uses absolute file name if only the name is given via the command line; closes #941

Author: hneemann

src/main/java/de/neemann/digital/gui/Main.java

@@ -2115,7 +2115,7 @@ public static void main(String[] args) {
             else if (s.trim().length() > 0) {
                 File f = new File(s);
                 if (f.exists())
-                    file = f;
+                    file = f.getAbsoluteFile();
             }
         }