Proposal: let's remove xxx_insert versions of algorithms taking OutputIterator

[awulkiew]

The algorithms:

• convex_hull_insert
• intersection_insert
• difference_insert
• simplify_insert
• sym_difference_insert
• union_insert

The main reason is that they take nonintuitive parameters, e.g. intersection_insert takes OutputIterator and in addition to this SingleGeometry because an iterator doesn't hold the necessary information for the algorithm to work. Another example is convex_hull_insert which takes the compile-time information Closure and Order from the input Geometry because the iterator doesn't hold it which can result e.g. in taking it from a Box while filling some unrelated output Range/Ring/Polygon with points.

Furthermore, they've been hidden in detail namespace so probably nobody uses them. But they have to be maintained.

What do you think?

[barendgehrels]

Fine for me.

If I remember correctly, we put them in detail years ago because we're not sure yet about their usefulness.

So they can be removed now.