maze brick and sprite editable

this is doing it the wrong way round I think.
```
var customColours = [
  "rgb(222, 3, 16)"
  "rgb(232, 47, 10)"
  "rgb(239, 81, 6)"
  "rgb(248, 115, 3)"
  "rgb(248, 146, 0)"
  "rgb(204, 161, 8)"
  "rgb(160, 175, 14)"
  "rgb(120, 188, 19)"
  "rgb(86, 187, 45)"
  "rgb(61, 172, 93)"
  "rgb(37, 156, 139)"
  "rgb(13, 139, 184)"
  "rgb(19, 115, 210)"
  "rgb(57, 81, 210)"
  "rgb(95, 48, 210)"
  "rgb(138, 11, 210)"
];

var colourMappings = (function() { 
  var map = {};
  customColours.forEach(function(c) {
    m[c] = "";
  };
  return map;
});
```