Fixed a few minor bugs with submitting solutions for Coding Contracts. Started on Getting STarted Guide for wiki

src/utils/helpers/is2DArray.ts

@@ -0,0 +1,8 @@
+// Checks whether an array is a 2D array.
+// For this, a 2D array is an array which contains only other arrays.
+// If one element in the array is a number or string, it is NOT a 2D array
+export function is2DArray(arr: any[]): boolean {
+    if (arr.constructor !== Array) { return false; }
+
+    return arr.every((e) => { return e.constructor === Array; });
+}