Support unitary operator with multiple letters

[pgwizardofoz]

jsep("x && !y") generates the correct AST:

{ type: 'LogicalExpression',
  operator: '&&',
  left: { type: 'Identifier', name: 'x' },
  right: 
   { type: 'UnaryExpression',
     operator: '!',
     argument: { type: 'Identifier', name: 'y' },
     prefix: true } }

If I add the new operators AND and NOT, the unitary operator is not correctly parsed

jsep.addBinaryOp("AND", 3);
jsep.addUnaryOp('NOT', 1);
jsep("x AND NOT y")

result in

{ type: 'Compound',
  body: 
   [ { type: 'BinaryExpression',
       operator: 'AND',
       left: { type: 'Identifier', name: 'x' },
       right: { type: 'Identifier', name: 'NOT' } },
     { type: 'Identifier', name: 'y' } ] }

Is there a way to support this?