improvements: Add FIXME for 'b' prefix

When composing the mapping table, codes for the characters are prefixed
with 'b', causing some inconsistency. It would be better to leave only
the binary representation, if possible.

compressor/core.py

@@ -219,6 +219,7 @@ def retrieve_table(dest_file: io) -> dict:
 
     chars = unpack('{}c'.format(offset), chars)
     codes = unpack('{}L'.format(offset), codes)
+    # FIXME: Remove 'b' prefix
     return {"b{0}".format(tobinary(code)): str(char, encoding=ENC)
             for char, code in zip(chars, codes)}