Support exclusion patterns from various VCS ignore lists.

* src/Makefile.am (tar_SOURCES): Add exclist.c
* src/common.h (EXCL_DEFAULT, EXCL_RECURSIVE)
(EXCL_NON_RECURSIVE): New flags.
(excfile_add, info_attach_exclist)
(info_cleanup_exclist,info_free_exclist)
(exclude_vcs_ignores): New prototypes.
* src/create.c (dump_dir0): Call info_attach_exclist.
* src/exclist.c: New file.
* src/incremen.c (scan_directory): Call info_attach_exclist.
* src/names.c (excluded_name): Moved to exclist.c. Change signature.
All uses updated.
* src/tar.c: New options: --exclude-ignore, --exclude-ignore-recursive
and --exclude-vcs-ignores.
(tar_stat_destroy): Free exclist.
* src/tar.h (tar_stat_info): New member exclude_list.

* NEWS: Document new exclusion options.
* doc/tar.texi: Likewise.
* doc/tar.1: Likewise.