Fix contours for face landmarks

[1j01]

• The contours had indices out of order, leading to ugly bridges across the mouth, eyes, and eyebrows.
• The lips are actually two loops, inner and outer. I implemented support for multiple loops in connectionsToIndices, but didn't add special handling for that case in the demo's rendering, since the only artifact is a line in the corner of the mouth, and it's pretty subtle. I didn't want to make any API changes, but I would ideally separate this into lipsInner and lipsOuter.
• The polygons are (still) not consistently clockwise or counter-clockwise.
• The eyebrows were not closed polygons. I added the left/right edges that join the top and bottom polylines to close these shapes.