Caesar connect respect connection env (#307)

* update caesar.py to respect panoptes connected endpoints when connecting to panoptes first

* update caesar.py so that it does not use _local of Panoptes

panoptes_client/caesar.py

@@ -19,9 +19,16 @@ class Caesar(object):
 
     def __init__(
         self,
-        endpoint='https://caesar.zooniverse.org',
+        endpoint=None,
         redirect_url='https://caesar.zooniverse.org/auth/zooniverse/callback'
     ):
+        _default_endpoint = 'https://caesar.zooniverse.org'
+        if Panoptes.client().endpoint == 'https://panoptes-staging.zooniverse.org':
+            _default_endpoint = 'https://caesar-staging.zooniverse.org'
+
+        if endpoint is None:
+            endpoint = _default_endpoint
+
         self.endpoint = endpoint
         self.headers = {
             'Accept': 'application/json'