Change ConstExpr to use a vector of (op, eudobj) pairs

[armoha]

// epScript example
const a = Db(336 * 1700);
const b = Db(336 * 1700);
const diff = b - a;  // subtraction between ConstExpr is not supported

Current Status

b - a
= (baseobj: b, offset: 0, rlocmode: 4) - (baseobj: a, offset: 0, rlocmode: 4)

Alternative

b - a 
= (opobjpairs: [(+, b),], offset: 0, rlocmode: 4) - (opobjpairs: [(+, a),], offset: 0, rlocmode: 4)
= (opobjpairs: [(+, b), (-, a)], offset: 0 - 0, rlocmode: 4)