make import a task of it's own

this allows us to distinguish it in the eventlog and apptask logic

src/eventlog.js

@@ -15,6 +15,7 @@ exports = module.exports = {
     ACTION_APP_REPAIR: 'app.repair',
     ACTION_APP_INSTALL: 'app.install',
     ACTION_APP_RESTORE: 'app.restore',
+    ACTION_APP_IMPORT: 'app.import',
     ACTION_APP_UNINSTALL: 'app.uninstall',
     ACTION_APP_UPDATE: 'app.update',
     ACTION_APP_UPDATE_FINISH: 'app.update.finish',