Concatenate window name into WM_CLASS

If you visit https://github.com/mooz/xkeysnail on Google
Chrome, xkeysnail will report WM_CLASS as follows:
  WM_CLASS 'Google-chrome' | active keymaps = ...

After applying this patch, it will be:
  WM_CLASS 'Google-chrome' (mooz/xkeysnail: Yet another
  keyboard remapping tool for X environment - Google
  Chrome)' | active keymaps = ...

This means we can change the keymaps according to the
window title.  This is especially useful when you want to
change the keymap for each tab of the browser.

This patch, however, forces changes to the user's config.py

If possible, I wanted to add the window title as the second
parameter of the lambda function given to "define_keymap",
but the current xkeysnail doesn't support it.

It looks like there's a change that adds a device name to
the second parameter, but It doesn't seem to be working
well.

xkeysnail/transform.py

@@ -17,9 +17,10 @@ def get_active_window_wm_class(display=Xlib.display.Display()):
     """Get active window's WM_CLASS"""
     current_window = display.get_input_focus().focus
     pair = get_class_name(current_window)
+    wmname = get_window_name(current_window, display)
     if pair:
         # (process name, class name)
-        return str(pair[1])
+        return str(pair[1]) + ' (' + str(wmname) + ')'
     else:
         return ""
 
@@ -40,6 +41,22 @@ def get_class_name(window):
     except:
         return None
 
+def get_window_name(window, display):
+    """Get window's name (recursively checks parents)"""
+    try:
+        wmname = window.get_full_text_property(
+            display.intern_atom('_NET_WM_NAME'),
+            display.get_atom('UTF8_STRING'))
+
+        if (wmname is None):
+            parent_window = window.query_tree().parent
+            if parent_window:
+                return get_window_name(parent_window, display)
+            return None
+        return wmname
+    except:
+        return None
+
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