Begin refactoring dispatcher into dispatcher and jobs objects
Update find_executable to use the shutil module.
Add a dictionary of dependencies. Its primary purpose is to avoid multiple
recursive searches when an executable is not found on the PATH.
Remove unnecessary _create_file_tuple.
Merge _get_java_path with find_executable.
Refactor nasp.py to use the configuration namedtuples.
Refactor read align jobs into objects
Refactor snpcaller jobs into objects
Add job command tests