Add possibility to change color of block category titles

[RuneCorp]

Expected Behavior

As a developer I would like to be able to change the color of the block category titles (such as "motors", "movements", "light" ++) to match the colors of the blocks. Currently they can only be gray as seen here:

[mrjacobbloom]

Although it's less convenient than a JS setting, you can use CSS to color these labels. Something like this might do the trick:

.scratchCategoryId-motors > .scratchCategoryMenuItemLabel { color: rgb(51, 115, 204); }