proxy_model.reset() in TasksView.update_mode_db added. Also hiding more columns in a view.
constants with harm_view couchdb strings + utility functions for installing it in db.
DBTableModel.get_jobs_db switched to permanent view, should also me fallback to temporary view, if view are not installed.
get_tasks_db permanent view added to constants.
update_db rewritten for work with new permenent view in database. Some clenups.