init return cb rpc

lib/http/rpc.js

@@ -2594,6 +2594,7 @@ RPC.prototype.blockToJSON = co(function* blockToJSON(entry, block, details) {
     version: entry.version,
     versionHex: util.hex32(entry.version),
     merkleroot: util.revHex(entry.merkleRoot),
+    coinbase: block.txs[0].inputs[0].script,
     tx: txs,
     time: entry.ts,
     mediantime: mtp,

lib/primitives/block.js

@@ -623,6 +623,7 @@ Block.prototype.getJSON = function getJSON(network, view, height) {
     ts: this.ts,
     bits: this.bits,
     nonce: this.nonce,
+    coinbase: this.txs[0].inputs[0].script,
     txs: this.txs.map(function(tx, i) {
       return tx.getJSON(network, view, null, i);
     }, this)