New version of TON golang library 💎 tonutils v1.2.0

1. Jettons support + examples
2. DNS domains support + examples
3. NFT Index field type changed to *big.Int
4. Send and return msg hash + find transaction by msg hash (by @iam047801)
5. Send and wait for transaction hash (by @iam047801)
6. Auto repeat send of external message when waiting for transaction more than expected.
7. Method for local check of contract code if it has specific method.
8. Added descriptions for contract method exec return codes
9. Fixed run get method workchain for masterchain addresses.
10. TLB loader/serializer fix of small size *big.Int
11. Onchain content serialize fix
12. GetByIntKey method for dictionary (get value using big.Int key instead of cell)
13. Increased test coverage

https://github.com/xssnick/tonutils-go