Added backup job status check to Cobalt.

This commit is focused on making several key changes to better support the Cobalt executor while also extending benefits of the change to all related scheduling system executors. The modification of a job script, prior to submissions, is now done in a standardize way through a series of methods in the augmenter package. This will avoid each executor approaching the solution in a potentially different way.

In addition to the changes to the augmenter Cobalt jobs will not echo a sentry line upon job completion. When no exit status can be derived, due to a delay in the CobaltLog, we will attempt to identify a successful job in this way. Any failure to identify a successful job will instead result in a more generalized, less confusing error message.

Finally, basic unit tests have been extended to all scheduler related executors. These are not meant to replace integration testing but to ensure basic workflows will not result in errors when encountered.

Closes #83 (closed)