Feature Request: remove items from the B+ Tree

[yuriescl]

This is a feature request for adding a remove(key) function, which removes an item (node) from the tree.

[NicolasLM]

I've been working on this feature for quite a while but I'm struggling with some edge cases: deleting really is more complicated than inserting. I hope to be done with it soon.

[SimonCqk]

Well done dude, I'm working on my personal database engined by B Tree (B+ Tree firstly, but edge cases drived me crazy...), I gonna adapt some of your designes !!