CMake project reloading.

[Olivier J. G.]

> Sorry, but I can't follow you on that last one, how is the tree a "master"
> of the model?

What I said makes a lot less sense to me now that I look at it again
this morning. In short, I should probably remove myself from this
discussion until I take the time to study the ProjectModel.
As I recall, what I was thinking last night was along the lines of
seamlessly replacing the items, so existing collections of items such
as the one SelectionController has and the ctxProjectItemList in the
ProjectManagerView plugin could continue processing without missing a
beat. At least as I explained it, it was certainly somewhat removed
from reality.
I would venture that the only thing I said that may be useful is that
instead of CMake reload being a delete all items and readd them, it
could instead create a new ProjectItem tree and compare it to the
existing tree, replacing as needed.
Even that though... I'll see if I can get a grip on this later today.

-Olivier JG