Fix a failure to reveal a key when all section keys have dependancies (#26)

Given the follownig scenario.

"mysection": {
    "type": "section",
    "title": "MyTitle",
    "keys": [
       "key1_revealed_on_condition_false",
       "key2_revealed_on_condition_false",
       "key3_revealed_on_condition_true",
       "key4_revealed_on_condition_true"
  ]
},

If the condition is "true" then keys 3 & 4 should be shown, but the bug causes key4 not to get drawn.
If the condition is "false" then keys 1 & 2 are shown correctly.

If a fifth key is added that does not define a dependancy then the problem does not occur.

Author: klangman

xapp/SettingsWidgets.py

@@ -251,7 +251,7 @@ def update_always_show_state(self):
 
     def check_reveal_state(self, *args):
         for revealer in self.revealers:
-            if revealer.props.child_revealed:
+            if revealer.props.reveal_child or revealer.props.child_revealed:
                 self.box.show_all()
                 self.frame.show()
                 return