An infinite loop in _CustomTextWrap on wide characters with width=1 #399

>>> import tabulate
>>> data = "\ud55c\uae00"  # 한글 -- each char is 2 display cols wide
>>> tabulate._CustomTextWrap(width=1).wrap(data) # infinite loop
Traceback (most recent call last):
  File "<python-input-17>", line 1, in <module>
    tabulate._CustomTextWrap(width=1).wrap(data) # infinite loop
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^