Backup utility tools

Usage example:

>>> from filetool.backup import backup_dir
>>> backup_dir("wallpaper", r"C:\downloads\wallpapers")
Perform backup 'C:\downloads\wallpapers'...
1. Calculate files...
    Done, got 20 files, total size is 4.50 MB.
2. Backup files...
    Write to 'wallpaper 2016-01-01 8h-54m-23s.zip'...
Complete!

There are three keywords ignore, ignore_ext and ignore_pattern is available for filtering out files you don’t want to backup. The API is similar to from_path_except().