Support for DNS Records

[dimiandre]

Resolver smart contract has these functions

• SetDNSRecords
• hasDNSRecords
• dnsRecord

that are helpful if someone needs to set for example a "A" record to a custom ipfs gateway (like me)

would be useful to have some helper functions to forge the transaction with ethjs. Right now there is no UI that supports it and there is no library as well, the only way is interacting manually with the contract using ABI