Add the ability to configure helios-testing by config file
Added ConfigTest

Refactored TemporaryJobs so users can now specify their own
deployer. We use this in the test to make sure that the jobs
are being built correctly using the values from the conf file.
Refactored ConfigTest

We now test a local profile and helios-ci profile. This also
allows us to test loading a profile by default (local), and
specifying one explicity (helios-ci). Also fixed issue where
prefix expression wasn't getting resolved when profile was
specified explicitly.
Merge pull request #182 from spotify/drewc/configtj

Add ability to configure helios-testing parameters by config-file