Fix getOrderbook (#970)

* Fix `getOrderbook` (Fix #766)
* Add `formatBidsAndAsks` as a recommended alternative to `getOrderbook`
* Add `renameCounterpartyToIssuer`

test/fixtures/rippled/requests/1-taker_gets-XRP-taker_pays-JPY.json

@@ -0,0 +1,13 @@
+{
+  "taker_gets": {
+    "currency": "XRP"
+  },
+  "taker_pays": {
+    "currency": "JPY",
+    "issuer": "rB3gZey7VWHYRqJHLoHDEJXJ2pEPNieKiS"
+  },
+  "ledger_index": "validated",
+  "limit": 400,
+  "taker": "rE9qNjzJXpiUbVomdv7R4xhrXVeH2oVmGR",
+  "command": "book_offers"
+}

test/fixtures/rippled/requests/2-taker_gets-JPY-taker_pays-XRP.json

@@ -0,0 +1,13 @@
+{
+  "taker_gets": {
+    "currency": "JPY",
+    "issuer": "rB3gZey7VWHYRqJHLoHDEJXJ2pEPNieKiS"
+  },
+  "taker_pays": {
+    "currency": "XRP"
+  },
+  "ledger_index": "validated",
+  "limit": 400,
+  "taker": "rE9qNjzJXpiUbVomdv7R4xhrXVeH2oVmGR",
+  "command": "book_offers"
+}

test/fixtures/rippled/requests/3-taker_gets-USD-taker_pays-XRP.json

@@ -0,0 +1,13 @@
+{
+  "taker_gets": {
+    "currency": "USD",
+    "issuer": "rvYAfWj5gh67oV6fW32ZzP3Aw4Eubs59B"
+  },
+  "taker_pays": {
+    "currency": "XRP"
+  },
+  "ledger_index": "validated",
+  "limit": 400,
+  "taker": "rE9qNjzJXpiUbVomdv7R4xhrXVeH2oVmGR",
+  "command": "book_offers"
+}

test/fixtures/rippled/requests/4-taker_gets-XRP-taker_pays-USD.json

@@ -0,0 +1,13 @@
+{
+  "taker_gets": {
+    "currency": "XRP"
+  },
+  "taker_pays": {
+    "currency": "USD",
+    "issuer": "rvYAfWj5gh67oV6fW32ZzP3Aw4Eubs59B"
+  },
+  "ledger_index": "validated",
+  "limit": 400,
+  "taker": "rE9qNjzJXpiUbVomdv7R4xhrXVeH2oVmGR",
+  "command": "book_offers"
+}

test/fixtures/rippled/responses/2-taker_gets-JPY-taker_pays-XRP-res.json

@@ -0,0 +1,6 @@
+{
+  "ledger_hash": "C4F68C1CF2E0BFC09284690067ED7B1A38D4509A09DF26D66EABCE4F196CE9E9",
+  "ledger_index": 42595629,
+  "offers": [],
+  "validated": true
+}