simple-cdd patches.

["Gustavo Franco" <stratus@debian.org>]

Hi list,

I did some small changes to simple-cdd, adding "local_packages_dir"
feature. I don't want list each package in "local_packages" (there are
many) and run a subshell with ls was a hack, so i've added
"local_packages_dir"[0]. The second patch fix a typo[1].

I would like to add "mixed release" support. Once i set the codename
to sarge, for example i would like to add packages from
sarge-backports release too. I thought it was possible through
"mirror_extras" but it lacks something that i'm not sure (maybe
debian-cd related). Hints are welcome.

[0] = http://svn.sacix.org.br/filedetails.php?repname=sacix&path=%2Futils%2Fsimple-cdd%2Fbuild-simple-cdd&rev=394&sc=0
[1] = http://svn.sacix.org.br/diff.php?repname=sacix&path=%2Futils%2Fsimple-cdd%2Fbuild-simple-cdd&rev=0&sc=0

Thanks,
-- stratus