Multiple select and removal in browser

[mikejbuckingham]

This PR fixes #198

For the time being, all we do here is enable selection of multiple rows, and provide the "Remove" functionality. In the future, it might be worth adding some extra options (such as view, but we need to decide how we're handling multiple-input views first (As mentioned in #218)

As we get cascade deletion of children when removing a parent, there is a situation where we're requesting th delete of an element that has already been removed. However, the DB code handles this quite gracefully, and I don't think it's the business of the viewer to intrude here. Would welcome feedback though (particularly as I plan to revisit the DB code in the near future)

[fvichot]

This looks like an internal Qt header, I don't think you should include it here.

[gpasquie]

It seems to work well for multiple deletion, good stuff.
However, I think there are some problems.
First, as you updated the contextual menu when you have multiple items selected, you'll need to update the "actions" toolbox on the left panel, otherwise the user can still have the feeling he can view or export multiple items.
Moreover, and it's a bit more complicated I think, you'll have to manage moving several items in the db...We can imagine being able to move multiple series at the same time but what do you do when you have a serie and a study selected at the same time? Should we disable drag and drop?
Or maybe we should allow multiple selection only for the same types of items but I'm not sure this is easily doable...

[rdebroiz]

Or maybe we should allow multiple selection only for the same types of items but I'm not sure this is easily doable...

+1

[ocommowi]

Is this solved or not? Should it be in 3.0 ?