Port Cassandra 2.0.6 script/conf bits to Titan zip

Updated the Cassandra configuration and shell script files we include
in the titan-$VERSION.zip file with changes from Cassandra 2.0.6.
I've retained Titan-specific modifications to bin/cassandra and
bin/nodetool that force use of the cassandra.in.sh file included in
the zip rather than any that might be present in /etc or the user's
homedir, but otherwise these files should now reflect their
counterparts in upstream as of 2.0.6.
Adding ES config files to Titan zipfile

This prepares the zipfile to switch from embedded ES to standalone ES.
The files in this commit are based on the upstream ES 1.1.1 release,
but they have a few customizations:

* configured relative paths starting with "db/" in elasticsearch.yml

* elasticsearch.in.sh changes directory to the top-level directory of
  the expanded zipfile.  This supports the relative paths in the
  previous bullet.

* added '-Des.path.conf=...' JVM parameter in the elasticsearch shell
  script that points it at the "conf" subfolder.  ES uses "config" by
  default, but we currently call that directory "conf" (as does
  Cassandra).
Helper program that tries a socket connection

I'm adding this to support titan.sh in the zipfile distribution.
titan.sh ideally wants to wait until Elasticsearch is completely
started and listening on its service port before attempting to start
Rexster.  It would also be convenient to wait until Rexster is
accepting connections on the RexPro port before returning from
titan.sh; titan.sh currently just forks Rexster and returns
immediately, which leaves a window of a few seconds after titan.sh
exits but before Rexster is fully initialized in which the user can
start rexster-console.sh and get a transient connection refusal error.
The Rexster thing is not as big a deal as the ES-before-Rexster thing
though.

Anyway, this commit is inelegant: for one thing, there are existing,
widely-available programs that I would rather use than write my own
util (e.g. telnet, nc, socat, netstat, nmap... any one of them could
fill the need in this case).  However, I don't want to introduce a new
command dependency into titan.sh if I can reasonably avoid it, and I
think this qualifies as reasonable.  CheckSocket also doesn't really
belong in titan-core, but I don't have another place to put it without
restructuring the titan-dist module just for this one source file.
Rewrite titan.sh to start ES as a separate process

In addition to the summary above, this commit adds blocking logic
after forking Rexster and ES during `titan.sh start`.  Now the script
waits until it can successfully connect to port 9300 (after starting
ES) and 8184 (after starting Rexster) before returning.
Update rexster-cassandra-es.xml

* Changed from embedded to standalone (connects to 127.0.0.1)

* Replaced outdated storage.index.foo Titan config keys with
  equivalent index.foo config keys
Deleting unused helper methods from titan.sh