Switch to Path for setting up config directory.

Also in this change ditch the resource manager for working out
the current working directory, the JVM provides this for us
(user.dir), much less can go wrong with this.

Change-Id: I5746ee043b5974df2b59eb9c586661ac815051d8
Reviewed-on: http://gerrit.dmdirc.com/4070
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>