Add embedable images (#564)

* Add embedable bitmaps

* Initial work on blob urls

* Finish implementing data url

* Fix some bugs

* Rename bitmap to image

* Fix loading image on document load

* Add transform properties for image

* Remove some logging

* Add image dimensions

* Implement system copy and paste

* Fix pasting images

* Fix test

* Address code review

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/document/layer_panel.rs

@@ -100,6 +100,7 @@ pub enum LayerDataTypeDiscriminant {
 	Folder,
 	Shape,
 	Text,
+	Image,
 }
 
 impl fmt::Display for LayerDataTypeDiscriminant {
@@ -108,6 +109,7 @@ impl fmt::Display for LayerDataTypeDiscriminant {
 			LayerDataTypeDiscriminant::Folder => "Folder",
 			LayerDataTypeDiscriminant::Shape => "Shape",
 			LayerDataTypeDiscriminant::Text => "Text",
+			LayerDataTypeDiscriminant::Image => "Image",
 		};
 
 		formatter.write_str(name)
@@ -122,6 +124,7 @@ impl From<&LayerDataType> for LayerDataTypeDiscriminant {
 			Folder(_) => LayerDataTypeDiscriminant::Folder,
 			Shape(_) => LayerDataTypeDiscriminant::Shape,
 			Text(_) => LayerDataTypeDiscriminant::Text,
+			Image(_) => LayerDataTypeDiscriminant::Image,
 		}
 	}
 }