Convert any number knobs especially in timeline widget to accept basic math

Similar to Nuke, add an ability in timeline widget or any number knob to add or subtract frames by inputting +, -, * and / to the value. For example, if the current frame is 1012, if the user enter +28 at the end of 1012 (1012 + 28), then hit enter, it will automatically show the total of the shot.