Cleanup
Refactor|App|Client: More convenient method for accessing a Config variable
UI|Updater: Use alternate accent color for annotation labels
Renderer|LensFX: Added a resizing filter (pixel density)

fx::Resize changes the size of the frame buffer to produce a pixelated
appearance, either for performance or aesthetic reasons.

The variables "Config.render.pixelDensity" and
"Config.render.fx.resize.factor" control the amount of resizing. The
former applies globally, however is only shown in Video Settings when
using a HiDPI display mode. The latter is accessible via the Renderer
Appearance editor.

The global pixel density setting replaces video mode resolution
config on OS X (changing the desktop video mode is not supported on
OS X).