tarfile.open: use os.statvfs.f_bsize as bufsize
rose bush: list: display resubmitted jobs

The old jobs of a task that has been resubmitted are not being displayed
in the list view. This change fixes that.

The time display is also improved as part of this change.
Merge pull request #987 from matthewrmshin/tarfile.open.bufsize

tarfile.open: use os.statvfs.f_bsize as bufsize
Merge pull request #988 from matthewrmshin/rose-bush.display-retry

rose bush: list: display resubmitted jobs
Update documentation URL
Merge pull request #990 from matthewrmshin/doc

Update documentation URL
Use `gzip` command to write `*.gz` files

At the time of this commit, Python's core `gzip` module is about 10X
slower than the `gzip` command.
Merge pull request #992 from matthewrmshin/gzip

Use `gzip` command to write `*.gz` files