Issue #1039466 We need to switch the file module for file and image fields even if they use a custom widget or they will not show up as fields that can be migrated. Best we can do is display anything that has a 'imagefield' or 'filefield' prefix.

Issue #1039466 Make sure number migration code does not break when migrating a field that has a custom number formatter.

Issue #1150790 Make sure empty values are not saved in migration to match bahavior when new empty values are submitted.

Issue #1093844 by dww, Fix PHP warnings from content_migrate.filefield.inc on undefined legacy settings.

Did some clean up of the List test and reverted the code that tried to check the module name for formatters, because it doesn't work.

#781088 Reorganize Content Migrate files for efficiency, and also to make it easier to use the individual module code as examples on how to implement the hooks.