fit-grains calls find-orientations if necessary

This pull request allows hexrd fit-grains to call find-orientations if it has not already been called.

A couple additional changes:

1. find-orientations saves its output to the `working_dir`, not the `analysis_dir`. This is necessary to allow multiple `fit-grains` analyses of the same set of orientations (for example, a time series during loading)

1. `find-orientations` output files are now `trial_orientations.dat`, `completeness.dat`, and `accepted_orientations.dat`. This seemed more descriptive and accessible to an end user.

1. some additional logging tweaks to the console to help break up long running operations that may include a call to `find-orientations` followed by multiple `fit-grains` analyses.