* Python 2.7 wheels for Windows are no longer being built (71, 73).
* A backwards-compatible change to the index file format, to accommodate seek
points at stream boundaries. Index files created with older versions of
`indexed_gzip` can still be loaded, but index files created with
`indexed_gzip` 1.6.0 cannot be loaded by older versions of `indexed_gzip`
(75).
* CRC and size validation of uncompressed data is now performed by default,
on the first pass through a GZIP file. This can be disabled by setting the
new `skip_crc_check` argument to `False` when creating an
`IndexedGzipFile`. Validation is not performed when an existing index is
imported from file (72).
* Null padding bytes at the end of a GZIP file, or in between GZIP streams,
are now skipped over (69, 70, 72).
* Seek points are now created at the beginning of every GZIP stream, in files
containing concatenated streams (72).