Switch to AutoClose instead of StreamUtils.

Change-Id: I07ed6c365c52470233ce2e56b262f6eb8456e874
Reviewed-on: http://gerrit.dmdirc.com/3791
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>
Update submodules: plugins (new commits)

plugins:
    607e82d Greg Holmes <greg@dmdirc.com>
            Switch to AutoClose instead of StreamUtils.

            Gerrit: http://gerrit.dmdirc.com/3793

Change-Id: I7db86ba79fc7837353ae12afef8fb1f01f4c07b2