Avoid identical colors being chosen on random

      close #4

canvas.js

@@ -129,7 +129,10 @@ let randomElement = function(selector) {
 
 document.getElementById('randomize').onclick = function(e) {
   randomElement('input[name="bg-color"]').checked = true;
-  randomElement('input[name="fg-color"]').checked = true;
+  do {
+    randomElement('input[name="fg-color"]').checked = true;
+  } while (document.querySelector('.colorpicker input[type="radio"][name="bg-color"]:checked').value
+	   == document.querySelector('.colorpicker input[type="radio"][name="fg-color"]:checked').value);
   randomElement('input[name="font"]').checked = true;
   randomElement('input[name="icon"]').checked = true;
   document.getElementById('step2value').value = document.getElementById('step2value').innerText = sampleTexts[Math.trunc(Math.random() * sampleTexts.length)];