Fix property getter for non-available properties

Properties which are not currently available weren't handled properly: The getter for a property that is not available with proptype 'str' would return "None" (as a string) instead of None. Trying to retrieve a non-available property with proptype 'int' would raise a TypeError, because the getter tries to call 'int(None)'. An alternative would be to raise some kind of exception for non-available properties, but I would prefer the getter to return None. For example None should be a valid value for the property 'path' if no video is loaded yet.

Author: Frechdachs

mpv.py

@@ -620,7 +620,8 @@ def _get_list(self, prefix, props):
 
 def bindproperty(MPV, name, proptype, access):
     def getter(self):
-        return proptype(_ensure_encoding(_mpv_get_property_string(self.handle, name.encode())))
+        value = _ensure_encoding(_mpv_get_property_string(self.handle, name.encode()))
+        return proptype(value) if value is not None else value
     def setter(self, value):
         _mpv_set_property_string(self.handle, name.encode(), str(proptype(value)).encode())
     def barf(*args):