Merge branch 'vega-charts' into horizon

Author: jpolitz

package-lock.json

@@ -38,6 +38,8 @@
     "source-map": "^0.5.7",
     "stacktrace-js": "^1.3.1",
     "strip-ansi": "^4.0.0",
+    "vega": "^6.1.2",
+    "vega-tooltip": "^1.0.0",
     "websocket": "^1.0.34",
     "ws": "^8.18.0"
   },

package.json

@@ -52,3 +52,4 @@ import image as _
 import image-typed as _
 import color as _
 import csv as _
+import charts as _