Add reconnect command

This is handy to test how well your cluster (and Kazoo) handle
reconnects. Can it recover your session? Can it reset the
watches (once this is supported by Kazoo)? etc..

Example:

(CONNECTED) /> session_info
state=CONNECTED
sessionid=0x1459b1f90650002
protocol_version=0
xid=1
last_zxid=4
timeout=10000
client=('127.0.0.1', 60359)
server=('127.0.0.1', 2181)
(CONNECTED) /> reconnect

(CONNECTING) />
(CONNECTED) /> session_info
state=CONNECTED
sessionid=0x1459b1f90650002
protocol_version=0
xid=1
last_zxid=4
timeout=10000
client=('127.0.0.1', 60360)
server=('127.0.0.1', 2181)

You can see a reconnected happen since your local end point
(i.e.: your source port) changed.

Signed-off-by: Raul Gutierrez S <rgs@itevenworks.net>