Support Cloud solr server using zookeeper url

[GoogleCodeExporter]

Currently SolrMeter supports only standalone Solr. But in many of cases, we 
need to check performance of not only standalone server but also cloud solr 
server based on SolrJ version 4.x

Original issue reported on code.google.com by [email protected] on 9 Mar 2015 at 8:34

[dortegau]

3 years ago we worked in a fork that includes this feature: https://github.com/idealista/solrmeter