Fast/convenient masking operations

[fbbdev]

Currently one can perform in-place or, andnot and xor operations with a range parameter through the addRange, removeRange and flip methods. Range-based and can be simulated by two consecutive calls to removeRange:

bitmap.removeRange(0, a);
bitmap.removeRange(b + 1, bitmap.maximum() + 1);

It would be more convenient to have a method family like, e.g., mask and maskClosed implementing the same functionality directly.

It would also be helpful to have a family of methods for performing range-restricted updates, i.e. something like

bitmap1.add(otherBitmap, rangeStart, rangeEnd);
bitmap2.flip(otherBitmap, rangeStart, rangeEnd);
bitmap3.andnot(otherBitmap, rangeStart, rangeEnd);

whose semantics would be

Roaring maskedOp;
maskedOp.addRange(rangeStart, rangeEnd);
maskedOp &= otherBitmap;

bitmap1 |= maskedOp;
bitmap2 ^= maskedOp;
bitmap3 -= maskedOp;

Specialized methods could probably be much faster and more memory-efficient than the mask-based solution above.