make traverse safe for delete operations

[shlomiassaf]

Currently, traverse does not play nice when mutating the children, signature, etc, of a reflection while traversing.

A current issue happens silently here

Every child is removed, but the iteration is done on the children collection:

    traverse(callback: TraverseCallback) {
        if (this.children) {
            this.children.forEach((child: DeclarationReflection) => {
                callback(child, TraverseProperty.Children);
            });
        }
    }

So the first child with index 0 is removed, then the index increments to 1 but because we altered the collection index 1 points to what used to be in index 2, i.e. we skipped an item.

The fix is simple, when working with collection work on a copy.

    traverse(callback: TraverseCallback) {
        if (this.children) {
            this.children.slice().forEach((child: DeclarationReflection) => {
                callback(child, TraverseProperty.Children);
            });
        }
    }

[shlomiassaf]

@aciccarello @blakeembrey can we kindly :) speed up PR merges?
I'm starting to pile up PR's and it creates a backlog 👍
thanks!

[aciccarello]

@shlomiassaf Thanks for the PRs. I'm really glad someone is making improvements. Sorry things are a bit behind. I don't have the time or knowledge of the codebase to process things very quickly. I'll see if I can get through the other 3 PRs sometime soon. Let me know if there is a priority. I'd guess #597 is the main blocker.

I'm also usually available on gitter if you need to discuss something.