Prune the Backup directory

[svenax]

After using Sublime Text with Package Control for some months, the Backup directory is starting to get pretty big. Sure, it is easy to delete old stuff there manually, but maybe it would be good to have an option to automatically prune backups older that X number of days. Good idea?

[franciscolourenco]

Actually it would be smarter to backup only what is important: the customization files. The rest can be downloaded from the interwebz..

[franciscolourenco]

Aren't customizations stored in ~/Library/Application Support/Sublime Text 2/Packages/User/?
Can they be overridden by a plugin upgrade?
Are we backing up these?

[franciscolourenco]

bump

[wbond]

Nothing has been done here. I'd be happy to have a PR to review.