update package to use fixed regl2d; add baseline image for new test

Author: ruijin

package-lock.json

@@ -110,7 +110,7 @@
     "polybooljs": "^1.2.0",
     "regl": "^1.6.1",
     "regl-error2d": "^2.0.11",
-    "regl-line2d": "^3.0.18",
+    "regl-line2d": "git://github.com/ruijin/regl-line2d.git#e9d0198ece05e135557e786d8815c23ed3fb0e9f",
     "regl-scatter2d": "^3.2.1",
     "regl-splom": "^1.0.12",
     "right-now": "^1.0.0",