Basic json parser with error handling.

Input examples

• \"Daniil Serov\"
• [[], [[]]]
• [[], [1], 2, [[3, [\" \"]]]]
• [1, {a: \"hello\", b: [1, 2, 3]}, null]
• {employees: [{John: {age: 20, car: null}}, {Anna: {age: 23, car: \"Lada\"}}]}