Add funding related rest endpoints, refactor pre-existent rest endpoints to use get_ prefix. Add function to calculate flags easily. Add example test to create a funding offer.

bfxapi/client.py

@@ -1,3 +1,4 @@
+from .rest import BfxRestInterface
 from .websocket import BfxWebsocketClient
 
 from typing import Optional
@@ -12,7 +13,20 @@ class Constants(str, Enum):
     PUB_WSS_HOST = "wss://api-pub.bitfinex.com/ws/2"
 
 class Client(object):
-    def __init__(self, WSS_HOST: str = Constants.WSS_HOST, API_KEY: Optional[str] = None, API_SECRET: Optional[str] = None, log_level: str = "WARNING"):
+    def __init__(
+            self,
+            REST_HOST: str = Constants.REST_HOST,
+            WSS_HOST: str = Constants.WSS_HOST,
+            API_KEY: Optional[str] = None,
+            API_SECRET: Optional[str] = None,
+            log_level: str = "WARNING"
+    ):
+        self.rest = BfxRestInterface(
+            host=REST_HOST,
+            API_KEY=API_KEY,
+            API_SECRET=API_SECRET
+        )
+
         self.wss = BfxWebsocketClient(
             host=WSS_HOST, 
             API_KEY=API_KEY,