Support UTF-16 Identifiers

[sinclairzx81]

This PR implements an update to support UTF-16 (unicode) schema identifiers, as well as refactoring similar logic for unicode object properties keys. In the case of schema identifiers, because schemas with identifiers are hoisted into their own functions (with the identifier used as the function name), this update encodes any non-alphanumeric character into it's unicode equivalent number as given by '...'.charCodeAt(index).

This update permits identifier URI's of the following form.

const Vector = Type.Object(
  {
    x: Type.Number(),
    y: Type.Number(),
    z: Type.Number(),
  },
  {
    $id: 'http://domain.com/schemas/Vector',
  },
)

const C = TypeCompiler.Compile(Vector)

console.log(C.Code())

// function check_http_58_47_47_domain_46_com_47_schemas_47_Vector(value) {
//   return (
//     (typeof value === 'object' && value !== null && !Array.isArray(value)) &&
//     (typeof value.x === 'number' && !isNaN(value.x)) &&
//     (typeof value.y === 'number' && !isNaN(value.y)) &&
//     (typeof value.z === 'number' && !isNaN(value.z))
//  )
// }
// return function check(value) {
//   return (
//     (check_http_58_47_47_domain_46_com_47_schemas_47_Vector(value))
//  )
// }

// ... with the identifier decodable with the following.
console.log(String.fromCharCode(58)) // :
console.log(String.fromCharCode(47)) // /
console.log(String.fromCharCode(47)) // /
console.log(String.fromCharCode(46)) // .