Oni: Add configuration for font smoothing (antialiasing)

[bryphe]

From @benjamin-rood 's feedback on gitter - would be helpful to have a configuration setting for setting / changing: webkit-font-smoothing on the body.

Perhaps ui.fontSmoothing with options of none, antialiased and subpixel-antialiased, and then just directly set the webkit-font-smoothing property from there.

[benjamin-rood]

Would also be worthwhile cf. how VS Code / Atom are implementing it.
Is this a feature anyone can fix via PR?

[bryphe]

FYI, looks like VSCode directly sets the -webkit-font-smoothing property with the workbench.fontAliasing config: https://github.com/Microsoft/vscode/blob/e27288074e0287a42d6752e20873c668526e8c4d/src/vs/workbench/electron-browser/workbench.ts#L935

[bryphe]

This is now available via ui.fontSmoothing configuration in master - some details here: https://github.com/onivim/oni/wiki/Configuration#ui

I'm planning on including this as part of the the 0.2.18 release tomorrow.

[benjamin-rood]

Merci Beaucoup!