Added a modified zkcli.bat script to overlay, this will be available after installation to interact with ZooKeeper.
Merge branch 'zkscript' of github.com:comperiosearch/openesp into comperiosearch-zkscript
Fixes #53

Merged in @rabagast pull request, added a modified zkcli.sh and
improved the script to print an error message if webapps/solr not yet
exists