Incremental builds: Delete doesn't work anymore

[feedm3]

When using this plugin, you cannot delete pages with incremental builds anymore. I guess it's because the copy doesn't remove files that are missing in the source folder, but only copies new pages or overwrites existing ones.

Some notes about this plugin
Due to some migration of routing rules, we had a need for this plugin at the beginning of our project. Now that the migration phase is over we removed it. After we removed the plugin, we figured out that the plugin had a very negative impact on incremental build and deployment times. Those are now reduced by over 50%! This is not an issue with smaller projects, but if you have a lot of pages (>10k pages) I would not recommend to use it.