rename WdpaImportWorker into ImportWorkers::MainWorker
rename MaintenanceSwitcher in WebHandler and add clear_cache
add clear_cache route to admin controller
add new FinaliserWorker for extra work at end of import
add clearing of Rails cache in FinaliserWorker
remove maintenance switcher from import.rb
test ImportTools::WebHandler#under_maintenance
Merge pull request #88 from unepwcmc/import-clears-cache

Import clears cache