- respecting a new env `$AUTOJUMP_DARWIN_XDG`: If `$XDG_DATA_HOME` is set, use it as the autojump's data home; else if the OS is macOS and `$AUTOJUMP_DARWIN_XDG` is false, use ~/Library (for compatibility); otherwise, use XDG's fallback path (i.e., `~/.local/share`).
- remove `migrate_osx_xdg_data( )` in autojump_data.py
- related issue: #447
The original implementation used str.encode() on input and str.decode() on
output. However this would cause UnicodeDecodeError since certain characters
can't be encoded / decoded in ASCII.
The new solution is to use unicode() on all input strings and output UTF-8
encoded strings. This makes the assumption that the shell can handle UTF-8
strings.
