Focus Bar for Magic Lantern

A simple post to say I've rationalised the focus bar script and it now runs in the background, and controllable from the ML FOCUS menu.

I have cleaned up the UI and it now blends into the overall ML UI.

The focus bar script (FOCUS) on the right has extensive info built in.

The overall functionality follows from previous versions, eg:

• I decided to keep the visualization of the focus field to a linear representation. I personally get more out of it this way. 
• In addition to 'seeing' the focus field, and the fp and dofs, you can decide if you wish to see the near and far distance info shown below the bar.
• For landscape photography, once the far dof is greater than 'infinity' the focus_bar distance reporting switches to total blur units (optical and diffraction in quadrature) at infinity for the far; and the dof distance based on the total infinity blur for the near dof.
• Blur reporting at infinity is green if above the sensor limit (2xsensor pixels) and red below (make sure you set the correct sensor info for your camera).
• The multiplier allows you to see the focus field beyond the far dof.
• A multiplier of -1 switches the focus bar into dof mode. Note in all modes the focus bar functions during Canon zoom. Hint: this may help portrait photographers or videographers looking to 'ensure' the focus field is 'right', ie use Canon zoom and focus on the eyes (say) and check the focus field, ie front vs back focus.
• A multiplier of 0 switches the focus bar into fp mode, ie see the focus field from zero to the fp.
• I think it 'best' to have ML diffraction aware on (diffraction impacted green dots showing dofs) and switch diffraction off in the focus bar. This way you can see the impact of diffraction in the focus field. The focus field is black at unity blur (optical or with diffraction if selected). Unity blur is defined as the calculated blur divided by the ML set blur (CoC).

Finally, as always, I welcome any feedback.