Allow Replace for Faster Deployment [Update After dev-stream]

[yasirroni]

Instead of add, compute, delete, add, compute, delete, ... this PR allows one to directly replace predefined index for LIFO (last in first out) technique.

For example, tree with 100 index (o-99), can specify index == 100 as LIFO index. Then, use tree[100] as insert point, compute CoDisp, and replace it with a new point (but same index).