0.4.0

Changes in this release involve modifications and additions to the IndexedGzipFile class to make it look and behave more like the built-in gzip.GzipFile class.

• __init__ accepts filename and mode as its first two parameters
• Changed default values for __init__ parameters to values which have been qualitatively tested
• readline, readlines, __iter__ and __next__ methods added, for iteration over lines in text data
• seek method accepts a whence parameter, and allows seeking from SEEK_SET or SEEK_CUR.