add option to disable active line highlighting in Code Settings

[kasparsj]

Hi Felix,
This is a proposal to add an option to enable/disable active line highlighting.
I personally find the option unclutters the code view.
Also neither Hydra has it (makes huge difference on visuals), nor Tidalcycles under Atom (Pulsar does highlight active line though).

[felixroos]

thanks, yes it's very good to have that option