Re import events

- Adds new fields to the Events table
- Adds models for new types (EuSuspensionRegulation, CitesSuspensionNotification)
- Updates README file to have information on Events
- Moves import files that were in the cleaned directory up a directory, as all files being used are cleaned
- Update rake tasks to find the import files in the new directory
- Renames import_laws, laws file, and related tasks, to use events instead of laws
- Updates events_import to use the new events file and to fill in the new Events' fields