Add speaker icon

CHANGELOG.md

@@ -45,6 +45,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   - `repeat`
   - `share`
   - `slack`
+  - `speaker`
   - `trending-down`
   - `trending-up`
   - `type`

icons/core/speaker.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+    <rect x="4" y="2" width="16" height="20" rx="2" ry="2" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/>
+    <circle cx="12" cy="14" r="4" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/>
+    <line x1="12" y1="6" x2="12" y2="6" fill="none" stroke="#000" stroke-linecap="round" stroke-linejoin="round" stroke-width="2"/>
+</svg>