Allow setting maxsize for PoolManager (#18)

* Allow setting maxsize for PoolManager

* Only customize maxsize if config is explicitly not set to None

configuration.py

@@ -30,9 +30,7 @@ from six.moves import http_client as httplib
 
 class ConfigurationObject(object):
     """
-    NOTE: This class is auto generated by the swagger code generator program.
-    Ref: https://github.com/swagger-api/swagger-codegen
-    Do not edit the class manually.
+    Configuration options for RESTClientObject
     """
 
     def __init__(self):
@@ -85,6 +83,13 @@ class ConfigurationObject(object):
         # Set this to True/False to enable/disable SSL hostname verification.
         self.assert_hostname = None
 
+        # urllib3 connection pool's maximum number of connections saved
+        # per pool. Increasing this is useful for cases when you are
+        # making a lot of possibly parallel requests to the same host,
+        # which is often the case here.
+        # When set to `None`, will default to whatever urllib3 uses
+        self.connection_pool_maxsize = None
+
     @property
     def logger_file(self):
         """

rest.py

@@ -99,6 +99,9 @@ class RESTClientObject(object):
             'key_file': key_file,
         }
 
+        if config.connection_pool_maxsize is not None:
+            kwargs['maxsize'] = config.connection_pool_maxsize
+
         if config.assert_hostname is not None:
             kwargs['assert_hostname'] = config.assert_hostname