Removing characterization save unless new_object?

Given that characterize is called via a Worker, we will usually have a
saved object. Do we need the new_object? guard for calling save.
Codifying a pid based job

Given that we are passing PIDs into jobs, we shouldn't assume that the
received PID will be for a Generic File. By using casting a base find
into the class we can more easily send other things through the various
jobs.
Merge pull request #169 from projecthydra/characterization-save-required

Removing characterization save unless new_object?