HALO cleanup & better drawables

Change-Id: I7afb5f1e473e9611059e1ea2acfaa9d307696449

Conflicts:
	packages/SystemUI/res/drawable-hdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-hdpi/halo_marker_r.png
	packages/SystemUI/res/drawable-mdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-mdpi/halo_marker_r.png
	packages/SystemUI/res/drawable-xhdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-xhdpi/halo_marker_r.png

Conflicts:

	packages/SystemUI/res/drawable-hdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-hdpi/halo_marker_r.png
	packages/SystemUI/res/drawable-mdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-mdpi/halo_marker_r.png
	packages/SystemUI/res/drawable-xhdpi/halo_marker_l.png
	packages/SystemUI/res/drawable-xhdpi/halo_marker_r.png