Issue #1928786 by iva2k, arthurf: adds a new reset to source option with tests, abstracts the tests to make it easier to test functionality'

Issue #1920280 by iva2k, arthurf: fixes namespace collision with core's file_load, handles file caching issue

Updates to use the core archiver functions. Unfortunately had to write new classes so that files can be stored in archives without full system paths.

Refactors the thumbnail generation. Working correctly now but need to think through derivative generation. File creation is still somewhat brittle but is functional.

Updates for the file edit process, renames the load function to make the menu handling easier and to make consistent with standard drupal terminonlogy. Probably should start thinking about moving the file pages to admin/content/files rather than under config

Working on improving some of the local file path handling. Ensuring that files are local for manipulation is turning out to be more difficult. Probably should provide a function to copy a file to the tmp directory so that all processing functions can work