ensure logplex boots when shard is down
boots shards in parallel

Rough implementation of booting shards in parallel. Still need to work
out shard replacement in a running system.
got shard reconfiguration working
self-healing redis shard failures

When a redis connection failure happens the logplex_redis_writer workers
will cycle trying to reconnect until a reconnect happens or the shards
are reconfigured.

Instead of using links to monitor the read and write buffers a monitor
is placed on the registered workers.
tweak timeout and minor style changes
add live_upgrade script

There is a record change inside the `logplex_shard` gen_sever that requires the server to be restarted. Both this
server and the `logplex_redis_writer_sup` are restarted to ensure all redis connections are reset.
ensure old pids are cleaned up
address concerns from PR

* removed use of `self` in favor of `self()`
* obtained Pid before reloading the module
Merge branch 'parallel-shard-load'