Fix label format for endless label types

Add some more documentation to config files
Create bar_codes directory to avoid IOExceptions when trying to write to non-existent directories

barcode_helpers.py

@@ -17,11 +17,11 @@ class BrotherLabelWriter(ImageWriter):
         if self.rot:
             self._h, self._w = label_type_specs[typ]['dots_printable']
             if self._w == 0 or self._w > max_height:
-                self._w = max_height
+                self._w = min(max_height, self._h / 2)
         else:
             self._w, self._h = label_type_specs[typ]['dots_printable']
             if self._h == 0 or self._h > max_height:
-                self._h = max_height
+                self._h = min(max_height, self._w / 2)
         self._xo = 0.0
         self._yo = 0.0
         self._title = text

conf.py

@@ -7,5 +7,7 @@ input_encoding = 'utf8'
 low_credit_warning_limit = -100
 user_recent_transaction_limit = 100
 
+# See https://pypi.org/project/brother_ql/ for label types
+# Set rotate to False for endless labels
 label_type = "29x90"
 label_rotate = True