BGZF support

[gtamazian]

BGZF is a GZIP-based block compression format widely used in bioinformatics. BGZF uses extra fields as specified in RFC 1952 and is designed to be compatible with GZIP decompressors.

The Gz.Inf module decompressor fails to read data from a BGZF file. The MWE with its input file:

$ decompress --format gzip mwe.txt.gz
decompress: Unexpected end of input.

I wonder why the current GZIP decompressor implementation fails to read BGZF and whether it can be easily fixed.

The input file mwe.txt.gz was created in the following way using the bgzip tool:

$ seq 1 10 > mwe.txt               
$ bgzip mwe.txt