Some of function is not matched with API spec

[ryukato]

Default information

• lbd-sdk-js version: 1.4.2

Description of the bug

Following sdk functions are not matched with API Spec

• parentOfNonFungibleToken: it has to return single NonFungibleId
• rootOfNonFungibleToken: it has to return single NonFungibleId

Missed sdk function for GET /v1/user-requests/{requestSessionToken}

[ryukato]

Being resolved by #106