用法是：[data, result]= readtext(source, delimiter, comment, quotes, options)
source: the file to be read. May be a file path or just the file name. OR: The text itself, see 'textsource', below.
delimiter: (default: ',') any non-empty string. May be a regexp, but this is slow on large files.
comment: (default: '') zero or one character. Anything after (and including) this character, until the end of the line, will be ignored.
quotes: (default: '') zero, one (opening quote equals closing), or two characters (opening and closing quote) to be treated as paired braces. Everything between the quotes will be treated as one item. The quotes will remain. Quotes may be nested.
options: (default: '') may contain (concatenate combined options):
- 'textsource': source contains the actual text to be processed, not the file name.
- 'textual': no numeric conversion ('data' is a cell array of strings only),
- 'numeric': everything is converted to a number or NaN ('data' is a numeric array, empty items are converted to NaNs unless 'empty2zero' is given),
- 'empty2zero': an empty field is saved as zero, and
- 'empty2NaN': an empty field is saved as NaN.
- 'usewaitbar': call waitbar to report progress.