Allow adjustment of the sliders via buttons

[gavinhenderson]

Is your feature request related to a problem? Please describe.
Sliders are annoying when you want to make fine changes or when you have gloves on using a touch screen device.

Describe the solution you'd like

Add a + and - button next to sliders to make changes with a tap or click

Additional context
Need to consider hold behaviour, should 'hold' continue to move the slider or only do one move so you have to keep tapping?