added howling-blocks.js example to README.md
added howling-blocks.js example to README.md

TonyGravagno/ScriptCraft,bgon/BlocklyCraft,ut7/ScriptCraft,walterhiggins/ScriptCraft,bgon/BlocklyCraft,TonyGravagno/ScriptCraft,bgon/BlocklyCraft,ut7/ScriptCraft,walterhiggins/ScriptCraft