Added a cast to string for the Dropdown default and choices values.

This allows using any printable object as choices list (some kings of Enums for instance), which is allowed by argparse but not by wxPython.

gooey/gui/components/widgets/dropdown.py

@@ -12,8 +12,9 @@ class Dropdown(TextContainer):
         return wx.ComboBox(
             parent=parent,
             id=-1,
-            value=default,
-            choices=[default] + self._meta['choices'],
+            # str conversion allows using stringyfiable values in addition to pure strings
+            value=str(default),
+            choices=[str(default)] + [str(choice) for choice in self._meta['choices']],
             style=wx.CB_DROPDOWN)
 
     def setOptions(self, options):