added some const functions to calculate leading and tailing noops, made
apply() and process() return Range<u64>. actors implementation is still
awful but will do them properly in the future
now everything that worked in 0.2 seems to work again, and should
actually be better. plus, merging differences is done properly and thus
should be way more reliable
working on this was really hard, so i'm making simple things first.
removed almost everything except bare buffer changes, and not even done
in a smart way, but should be a working PoC? now trying to make a
working client to test it out and actually work on a real prototype
