fixes based on comments

plugins/zookeeper/README.md

@@ -0,0 +1,62 @@
+## Telegraf Plugin: Zookeeper
+
+#### Description
+
+The zookeeper plugin collects variables outputted from the 'mntr' command
+[Zookeeper Admin](https://zookeeper.apache.org/doc/trunk/zookeeperAdmin.html).
+
+```
+echo mntr | nc localhost 2181
+
+              zk_version  3.4.0
+              zk_avg_latency  0
+              zk_max_latency  0
+              zk_min_latency  0
+              zk_packets_received 70
+              zk_packets_sent 69
+              zk_outstanding_requests 0
+              zk_server_state leader
+              zk_znode_count   4
+              zk_watch_count  0
+              zk_ephemerals_count 0
+              zk_approximate_data_size    27
+              zk_followers    4                   - only exposed by the Leader
+              zk_synced_followers 4               - only exposed by the Leader
+              zk_pending_syncs    0               - only exposed by the Leader
+              zk_open_file_descriptor_count 23    - only available on Unix platforms
+              zk_max_file_descriptor_count 1024   - only available on Unix platforms
+```
+
+## Measurements:
+#### Zookeeper measurements:
+
+Meta:
+- units: int64
+- tags: `server=<hostname> port=<port>`
+
+Measurement names:
+- avg_latency
+- max_latency
+- min_latency
+- packets_received
+- packets_sent
+- outstanding_requests
+- znode_count
+- watch_count
+- ephemerals_count
+- approximate_data_size
+- followers #only exposed by the Leader
+- synced_followers #only exposed by the Leader
+- pending_syncs #only exposed by the Leader
+- open_file_descriptor_count
+- max_file_descriptor_count
+
+#### Zookeeper string measurements:
+
+Meta:
+- units: string
+- tags: `server=<hostname> port=<port>`
+
+Measurement names:
+- zk_version
+- server_state