rather than printing "getting sources/building/configuring/etc" for every single package, handle it in retro_packages.sh
automatically. This allows for some de-duplication and more consistent output. Also handle it from a function which allows
for some more compact code in retropie_packages.sh
Merge pull request #368 from joolswills/info

rather than printing "getting sources/building/configuring/etc" for ever...