Rewrite to use the pure JS zookeeper client library

- [x] Fix tests 
- [x] travis 
- [x] the vm

> The purejs `node-zookeeper-client` does throw when some unexpected things happen so some `try`s are probably needed in here.

^ This is not plausible unfortunately. There are about 40 places where this can throw if zookeeper does something unexpected. Not sure how much of an issue this is.
test you get an error when the lock is `''`