Auto-update rates when salaries or work pattern changes Merged

Currently its a manual process to update hourly/daily rates on the employee record following a change in salary or work pattern. This is easily missed and is not flagged by system warnings, meaning there is a real danger of employees being paid incorrectly. The manual change is also a time consuming process, especially when there are many employees on the payroll. Particularly dangerous when linked to HR which changes salaries without visiting the employee screen.