partially reversed part of the previous commit with respect to integers and strings; an Integer is now a low-level structure same as strings/arrays/relations/etc rather than being a type of Capsule; a String is now once again a string of integers in general, including negative ones, rather than only allowing non-negatives; the net effect is that String is now fully unchanged from a week prior in meaning, and Integer has ended up with a less drastic change from a week prior than otherwise