message: add getDefaultBurnAddress() for getting the default burn address in all networks
diff: @@ -41,6 +41,10 @@ export class BlockstackNetwork {
  return bitcoinjs.address.toBase58Check(addressHash, this.layer1.pubKeyHash)
  }
  + getDefaultBurnAddress() {
  + return this.coerceAddress('1111111111111111111114oLvT2')
  + }
  +
  getNamePrice(fullyQualifiedName: string) {
  return fetch(`${this.blockstackAPIUrl}/v1/prices/names/${fullyQualifiedName}`)
  .then(resp => resp.json())
  