GenericProjectManager improvements

[Niko Sams]

Don't know if I have understood this correctly: One instance can watch one
directory or one file - right?

> For others 1 KDirWatcher/Project might
> be enough most of the time.
I can't think of an ProjectManager that just needs one. You always want to
refresh the whole directory structure of the project.

>  Use 1 KDirWatch per project manager - or maybe project
What should this watch?

Niko