Add support for multiple files to bgzip

Reimplemented to reduce complexities.
Update to avoid test failure in windows
Updated to work with shared stdin/out hfile

bgzip.1

@@ -4,7 +4,7 @@
 bgzip \- Block compression/decompression utility
 .\"
 .\" Copyright (C) 2009-2011 Broad Institute.
-.\" Copyright (C) 2018, 2021-2022 Genome Research Limited.
+.\" Copyright (C) 2018, 2021-2023 Genome Research Limited.
 .\"
 .\" Author: Heng Li <lh3@sanger.ac.uk>
 .\"
@@ -54,7 +54,7 @@ bgzip \- Block compression/decompression utility
 .IR size ]
 .RB [ -@
 .IR threads ]
-.RI [ file ]
+.RI [ file " ...]"
 .PP
 .SH DESCRIPTION
 .PP
@@ -70,7 +70,8 @@ If the -c option is used, the result will be written to standard output,
 otherwise when compressing bgzip will write to a new file with a .gz
 suffix and remove the original.  When decompressing the input file must
 have a .gz suffix, which will be removed to make the output name.  Again
-after decompression completes the input file will be removed.
+after decompression completes the input file will be removed. When multiple
+files are given as input, the operation is performed on all of them.
 
 .SH OPTIONS
 .TP 10