Added a third parameter to ISize: reach. Three reach types: short, medium, and far. Without an item or with a non-ISize item, the player's reach is "short" which is 0.75 * the normal reach distance (default to 4 in survival, 5 in creative). Medium reach items/ tools have 1 * the normal distance and far reach items have 1.25 *. Items like knives have a short reach, javelins have a long one.

For reference: tools with a 'short' reach:
knife, saw, chisel, pro-pick, (bow), buckets, firestarter, flint and steel, gold pan

medium:
sword, mace, pickaxe, hammer, axe

far:
javelin, scythe, shovel, rope, hoe, fishing rod