feature/stat-script

[cheakimsemao]

added stat script

[Socret360]

1. Don't need to have is_directory function. os.path.isdir already returns a boolean.
2. Update the description in parser.add_argument and AssertError description too.
3. Don't + "/" use os.path.join instead. + "/" will cause an error on windows.
4. The code goes through the entire dataset twice. Once for reading the text boxes and onces for counting the characters. You can make adjust to only goes through the dataset once.
5. The function and variable names that has "word" in them is not accurate. Each textboxes contains a line (not a word). Should rename strip_words and split_words to strip_line and split_line respectively.