Add a basic quotes-only robinhood backend

We need a yank to test the order system and other end points that
require auth.

Resolves #2

piker/brokers/robinhood.py

@@ -0,0 +1,52 @@
+"""
+Robinhood API backend.
+"""
+import asks
+from async_generator import asynccontextmanager
+
+from ..log import get_logger
+from ._util import resproc
+
+log = get_logger('robinhood')
+
+_service_ep = 'https://api.robinhood.com'
+
+
+class _API:
+    """Robinhood API endpoints exposed as methods and wrapped with an
+    http session.
+    """
+    def __init__(self, session: asks.Session):
+        self._sess = session
+
+    async def _request(self, path: str, params=None) -> dict:
+        resp = await self._sess.get(path=f'/{path}', params=params)
+        return resproc(resp, log)
+
+    async def quotes(self, symbols: str) -> dict:
+        return await self._request('quotes/', params={'symbols': symbols})
+
+    async def fundamentals(self, symbols: str) -> dict:
+        return await self._request('fundamentals/', params={'symbols': symbols})
+
+
+class Client:
+    """API client suitable for use as a long running broker daemon or
+    single api requests.
+    """
+    def __init__(self):
+        self._sess = asks.Session()
+        self._sess.base_location = _service_ep
+        self.api = _API(self._sess)
+
+    async def quote(self, symbols: [str]):
+        resp = await self.api.quotes(','.join(symbols))
+        results = resp['results']
+        return {sym: quote for sym, quote in zip(symbols, results)}
+
+
+@asynccontextmanager
+async def get_client() -> Client:
+    """Spawn a RH broker client.
+    """
+    yield Client()