Add option to also reimport projects when exporting working sets

[fabioz]

This is a feature request.

The idea would be exporting the existing projects locations too when exporting working sets and when restoring, reimport the existing projects and then restore the working sets (or maybe creating a separate action for that).

My use case is that usually I have a single folder for all my projects and then a workspace is a subset of those projects where I import just the projects I'm interested in the workspace (so, it's annoying reimporting each one manually).

[iloveeclipse]

@fabioz : thanks. I'm currently busy, but I will try to review that soon.