Commit d2ae92b4b3 patched up the download counter and progress
display. Yum no longer provides the needed information so now we get the
total number of packages from the start of the transaction.
This also turns off colors when stdout is not a tty, and only prints the
install progress once so that piping to a logfile isn't flooded with
useless characters.
We should probably let the user know if something goes wrong with the
transaction or if a scriptlet fails. So: log the messages so we can find
(and, one hopes, fix) them later.
It used to give us (x/y) packagename, but now it only sends package
name. This was changed in yum commit 7e8c76173. For now default to
showing the zeros along with the package name so that it doesn't look
like an error.