Add "modifying" typeclasses #7
Description
When trying to use this package I was surprised to find that the Update typeclasses don't "modify" a field in a tuple, but instead just set it. This means that if you want to modify a field by first taking its value you would have to separately select, then update.
It would be good to have a selection of typeclasses that modify a particular field of a tuple, instead of just setting it.