Support ljdump.config filename as argument for those who would like
to automate multiple account backups and thus need to run ljdump with
different ljdump.config files.

Patched as suggested from http://ljdump.livejournal.com/12125.html

Data-source: Dennis Yurichev <dennis@yurichev.com>
Signed-off-by: David McNett <nugget@macnugget.org>
Add *.config ignore wildcard to protect against inadvertant committing
of local config files.