Start using nio2 in resource managers.

Change-Id: Ibac8f73683eec322d28cd10ced08c8777812ac43
Depends-On: I2f9f58595e0867db798c1930d5a90975bab296f8
Reviewed-on: http://gerrit.dmdirc.com/3510
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>