Thanks to TGC for his json fix

Also fixes some setting upgrades that I inadvertantly missed. As found by superfly

lp:~phill-ridout/openlp/tgcs_json_fix (revision 2766)
[SUCCESS] https://ci.openlp.io/job/Branch-01-Pull/2187/
[SUCCESS] https://ci.openlp.io/job/Branch-02-Functional-Tests/2090/
[SUCCESS] https://ci.openlp.io/job/Branch-03-Interface-Tests/1977/
[SUCCESS] https://ci.openlp.io/job/Branch-04a-Code_Analysis/1347/
[SUCCESS] https://ci.openlp.io/job/Branch-04b-Test_Coverage/1183/
[SUCC...

bzr-revno: 2765

openlp/core/common/json.py

@@ -40,7 +40,8 @@ class OpenLPJsonDecoder(JSONDecoder):
         self.kwargs = kwargs
         if object_hook is None:
             object_hook = self.custom_object_hook
-        super().__init__(object_hook, parse_float, parse_int, parse_constant, strict, object_pairs_hook)
+        super().__init__(object_hook=object_hook, parse_float=parse_float, parse_int=parse_int,
+                         parse_constant=parse_constant, strict=strict, object_pairs_hook=object_pairs_hook)
 
     def custom_object_hook(self, obj):
         """
@@ -71,7 +72,9 @@ class OpenLPJsonEncoder(JSONEncoder):
         self.kwargs = kwargs
         if default is None:
             default = self.custom_default
-        super().__init__(skipkeys, ensure_ascii, check_circular, allow_nan, sort_keys, indent, separators, default)
+        super().__init__(skipkeys=skipkeys, ensure_ascii=ensure_ascii, check_circular=check_circular,
+                         allow_nan=allow_nan, sort_keys=sort_keys, indent=indent, separators=separators,
+                         default=default)
 
     def custom_default(self, obj):
         """

openlp/core/common/settings.py

@@ -262,7 +262,10 @@ class Settings(QtCore.QSettings):
         ('core/recent files', 'core/recent files', [(file_names_conv, None)]),
         ('media/media files', 'media/media files', [(file_names_conv, None)]),
         ('presentations/presentations files', 'presentations/presentations files', [(file_names_conv, None)]),
-        ('core/logo file', 'core/logo file', [(str_to_path, None)])
+        ('core/logo file', 'core/logo file', [(str_to_path, None)]),
+        ('presentations/last directory', 'presentations/last directory', [(str_to_path, None)]),
+        ('images/last directory', 'images/last directory', [(str_to_path, None)]),
+        ('media/last directory', 'media/last directory', [(str_to_path, None)])
     ]
 
     @staticmethod

openlp/plugins/images/imageplugin.py

@@ -41,6 +41,7 @@ __default_settings__ = {
     'images/db hostname': '',
     'images/db database': '',
     'images/background color': '#000000',
+    'images/last directory': None
 }
 
 

openlp/plugins/media/mediaplugin.py

@@ -42,7 +42,8 @@ log = logging.getLogger(__name__)
 # Some settings starting with "media" are in core, because they are needed for core functionality.
 __default_settings__ = {
     'media/media auto start': QtCore.Qt.Unchecked,
-    'media/media files': []
+    'media/media files': [],
+    'media/last directory': None
 }
 
 

openlp/plugins/presentations/presentationplugin.py

@@ -47,7 +47,8 @@ __default_settings__ = {'presentations/override app': QtCore.Qt.Unchecked,
                         'presentations/presentations files': [],
                         'presentations/thumbnail_scheme': '',
                         'presentations/powerpoint slide click advance': QtCore.Qt.Unchecked,
-                        'presentations/powerpoint control window': QtCore.Qt.Unchecked
+                        'presentations/powerpoint control window': QtCore.Qt.Unchecked,
+                        'presentations/last directory': None
                         }