Store mappings in Zookeeper:

All dictionaries, except dpset, are stored remotely
in Zookeeper.
A dictionary dict with entries of the form:
key => value
is represented in the Zookeeper as a parent znode,
named "dict", followed by a number of child znodes,
each of which stands for a key:value pair, with the
znode's name being "key", and znode's data being "value".

For example, a dictionary dict with two entries:
{id1:name1, id2:name2}
is represented in Zookeeper as follows:
Parent znode: (name=dict, data=None)
Child znodes: (name=id1, data=name1);
      	      (name=id2, data=name2).