Add support for Ephemeral nodes in InMemoryConnection

[ezbz]

See:

https://github.com/erezmazor/projectx/blob/master/org.projectx.zookeeper/src/test/java/org/projectx/zookeeper/TestInMemoryConnection.java

For how

[jzillmann]

Changed the code a bit to start with 0 instead of 1 (like zookeeper is doing) and to make it also work for persistent sequentials.