Don't print to stdout in reindex command

This makes the tests quieter and allows calling scripts to control
whether they want output to be printed or not.
Close mongoose connection after reindexing

Because this command can be called in the context of a request we don't
want to end up with lots of open database connections, so make sure we
close the connection after using it.
Update elasticsearch to 1.5.1

Works around bug with elasticsearch's client.close(), which used to wait
until maxKeepAliveTime elapsed before exiting, which is 5 minutes by
default. This was fixed in 1.5.1.
Merge pull request #28 from mysociety/reindex-script-changes

Reindex script changes