Need .png assets for mutator/comment/warning icons

See web SVG examples by importing the following:

<workspace>
  <block type="procedures_ifreturn" x="313" y="113">
    <mutation value="1"></mutation>
  </block>
  <block type="procedures_defnoreturn" x="313" y="163">
    <field name="NAME">do something</field>
    <comment pinned="false" h="80" w="160">Describe this function...</comment>
  </block>
</workspace>