Canvas zooming (#716)

* Zoom icons.

* Actions.

* Min zoom of 0 does not make sense.

* Zoom logic.

* Modify how zoom affects selection rendering.

* More precise scrollbar dimensions.

* Adjust elements visibility and scrollbars.

* Normalized canvas width and height.

* Apply zoom to resize test.

* [WIP] Zoom using canvas center as an origin.

* Undo zoom on `getScrollBars`.

* WIP: center zoom origin via scroll

* This was wrong for sure.

* Finish scaling using center as origin.

* Almost there.

* Scroll offset should be not part of zoom transforms.

* Better naming.

* Wheel movement should be the same no matter the zoom level.

* Panning movement should be the same no matter the zoom level.

* Fix elements pasting.

* Fix text WYSIWGT.

* Fix scrollbars and visibility.

src/locales/en.json

@@ -53,7 +53,9 @@
     "getShareableLink": "Get shareable link",
     "close": "Close",
     "selectLanguage": "Select Language",
-    "scrollBackToContent": "Scroll back to content"
+    "scrollBackToContent": "Scroll back to content",
+    "zoomIn": "Zoom in",
+    "zoomOut": "Zoom out"
   },
   "alerts": {
     "clearReset": "This will clear the whole canvas. Are you sure?",