Interacting via ZMQ

An example:
```python

import zmq
import gym
from gym import spaces

class ZMQConnection:

def __init__(self, ip, port):
self._ip = ip
self._port = port

self._context = zmq.Context()
self._socket = self._context.socket(zmq.REQ)
self._socket.connect("tcp://{}:{}".format(ip, port))

@property
def socket(self):
return self._socket

def sendreq(self, msg):
self.socket.send_json(msg)
respmsg = self.socket.recv_json()
return respmsg

class POMDPsZMQEnv(gym.Env):

def __init__(self, ip='127.0.0.1', port=9393):
self._conn = ZMQConnection(ip, port)

def _step(self, action):
data = self._conn.sendreq({"cmd": "step", "args": int(action + 1)})
assert 'obs' in data
assert 'rew' in data
assert 'done' in data
assert 'info' in data
return data['obs'], data['rew'], data['done'], data['info']

def _reset(self):
data = self._conn.sendreq({"cmd": "reset"})
assert 'obs' in data
return data['obs']

@property
def action_space(self):
data = self._conn.sendreq({"cmd": "n_actions"})
assert 'n_actions' in data
return spaces.Discrete(data['n_actions'])

@property
def observation_space(self):
data = self._conn.sendreq({"cmd": "obs_dimensions"})
assert 'obs_dim' in data
return spaces.Box(-10, 10, shape=tuple(data['obs_dim']))

if __name__ == '__main__':
env = POMDPsZMQEnv()
obs = env.reset()
while True:
action = env.action_space.sample()
ob, reward, done, _ = env.step(action)

print("s ->{}".format(obs))
print("a ->{}".format(action))
print("sp->{}".format(ob))
print("r ->{}".format(reward))

obs = ob
if done:
break

env.close()
```