Dataframe (#576)

* initial dataframe commit

* initial dataframe port of core app

* rename variables for clarity

* remove unused import

* comment out unused code

* fix array handling bug in crossfilter dimension creation

* allow creation of empty dataframes

* handle non-existent columns

* handle non-existent columns

* revise tests for new dataframe

* comments for clarity

* comments for clarity

* generate bulk add placeholder with real gene names

* fix bug in gene name adding

* more dataframe unit tests

* fix bug - subset from current world, not universe

* put cut and pasted code into a single function

* improve caching of crossfilter

* remove cascading update bug from graph

* more performance work

* improve state handling for scatterplot

* performance optimization of critical path

* add column summarization

* dataframe utils

* add callOnceLazy

* fix tests

* minor updates found during review

* fix misspelling

* remove RESTv02 from function names

* comment cleanup

* cut/icut col parameter defaults to null

* break up large test

* improve tests and comments on dataframe at/has functions

client/src/util/dataframe/util.js

@@ -0,0 +1,28 @@
+/*
+Private utility code for dataframe
+*/
+
+export function isTypedArray(x) {
+  return (
+    ArrayBuffer.isView(x) &&
+    Object.prototype.toString.call(x) !== "[object DataView]"
+  );
+}
+
+export function isArrayOrTypedArray(x) {
+  return Array.isArray(x) || isTypedArray(x);
+}
+
+export function callOnceLazy(f) {
+  let value;
+  let calledOnce = false;
+  const result = function result(...args) {
+    if (!calledOnce) {
+      value = f(...args);
+      calledOnce = true;
+    }
+    return value;
+  };
+
+  return result;
+}