This MR solves most (if not all) performance issues that we encountered with ListView. I will later go through the issues and see one-by-one, but from testing it seems so.
Please review.
Note that I had to rebase this branch to the current master.
Later, fix for #211 (closed) was added.
Fixes #201 (closed) #211 (closed)
Edited by Marko Vendelin