Commons of Python micro-functions. This is basically an out-sourced, shared
utils module.

Rules:

- Cannot depend on anything except the standard library

Functions:

- is_sequence: check if something is list-ish
- is_mapping: check if an object is dict-ish
- ensure_list: make sure an argument is a list, or make it into a single-element
               list
- clean_dict: remove null values from a dict, recursively
- decode_path: decode a path name to be unicode
- hash_data: generate a SHA1 from a dict of reasonable objects

WWW: https://github.com/pudo/banal