truncating and testing truncation to 63 variables

(cherry picked from commit d1c15ec)

Author: monfera

src/traces/parcoords/defaults.js

@@ -34,6 +34,8 @@ function dimensionsDefaults(traceIn, traceOut) {
 
     var dimensionIn, dimensionOut;
 
+    dimensionsIn.splice(63); // parcoords supports up to 63 dimensions
+
     function coerce(attr, dflt) {
         return Lib.coerce(dimensionIn, dimensionOut, attributes.dimensions, attr, dflt);
     }