Added new brazillian exchange to exchange rates plugin: Walltime.

electrum/currencies.json

@@ -897,5 +897,8 @@
     ],
     "Biscoint": [
         "BRL"
+    ],
+    "Walltime": [
+        "BRL"
     ]
 }

electrum/exchange_rate.py

@@ -411,6 +411,14 @@ class Biscoint(ExchangeBase):
         return {'BRL': Decimal(json['data']['last'])}
 
 
+class Walltime(ExchangeBase):
+
+    async def get_rates(self, ccy):
+        json = await self.get_json('s3.amazonaws.com', 
+                             '/data-production-walltime-info/production/dynamic/walltime-info.json')
+        return {'BRL': Decimal(json['BRL_XBT']['last_inexact'])}
+
+
 def dictinvert(d):
     inv = {}
     for k, vlist in d.items():