Add node modules and compiled JavaScript from main (#172)

Co-authored-by: Oliver King <oking3@uncc.edu>

node_modules/underscore/modules/lastIndexOf.js

@@ -0,0 +1,6 @@
+import findLastIndex from './findLastIndex.js';
+import createIndexFinder from './_createIndexFinder.js';
+
+// Return the position of the last occurrence of an item in an array,
+// or -1 if the item is not included in the array.
+export default createIndexFinder(-1, findLastIndex);