Fix config file reading

Now use helios-base.conf and helios.conf as config files.
Won't conflict with any other Typesafe config things the
project might be using.  Also fixes the client creation
code in TemporaryJobs to not stomp on an existing client
if the domain/endpoints, etc. was set in the config file.
Merge pull request #193 from spotify/drewc/config-rework

Fix config file reading