Add a new keyword argument expiretime to nosql.py

Allow NoSqlManager to accept a new keyword argument expire, which is
accepted as an optional argument by the method set_value in redis.py to
specify the expire time in seconds for the session object

.gitignore

@@ -1,3 +1,5 @@
 *.py?
 *.egg-info
 *.swp
+build/
+dist/

beaker_extensions/nosql.py

@@ -13,7 +13,7 @@
 log = logging.getLogger(__name__)
 
 class NoSqlManager(NamespaceManager):
-    def __init__(self, namespace, url=None, data_dir=None, lock_dir=None, **params):
+    def __init__(self, namespace, url=None, data_dir=None, lock_dir=None, expire=None, **params):
         NamespaceManager.__init__(self, namespace)
 
         if not url:
@@ -26,6 +26,8 @@ def __init__(self, namespace, url=None, data_dir=None, lock_dir=None, **params):
         if hasattr(self, 'lock_dir'):
             verify_directory(self.lock_dir)           
 
+        self._expiretime = int(expire) if expire else None
+
         conn_params = {}
         parts = url.split('?', 1)
         url = parts[0]
@@ -60,7 +62,7 @@ def set_value(self, key, value):
         self.db_conn[self._format_key(key)] =  pickle.dumps(value)
 
     def __setitem__(self, key, value):
-        self.set_value(key, value)
+        self.set_value(key, value, self._expiretime)
 
     def __delitem__(self, key):
         del self.db_conn[self._format_key(key)]