Add IDs to elements (#236)

* Add IDs to elements

- Move round rect function within the renderer

* Generate IDs using nanoid

* If element ID does not exist, add the ID during restoration

package-lock.json

@@ -1473,6 +1473,7 @@
       "version": "24.0.25",
       "resolved": "https://registry.npmjs.org/@types/jest/-/jest-24.0.25.tgz",
       "integrity": "sha512-hnP1WpjN4KbGEK4dLayul6lgtys6FPz0UfxMeMQCv0M+sTnzN3ConfiO72jHgLxl119guHgI8gLqDOrRLsyp2g==",
+      "dev": true,
       "requires": {
         "jest-diff": "^24.3.0"
       }
@@ -1487,6 +1488,14 @@
       "resolved": "https://registry.npmjs.org/@types/minimatch/-/minimatch-3.0.3.tgz",
       "integrity": "sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA=="
     },
+    "@types/nanoid": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/@types/nanoid/-/nanoid-2.1.0.tgz",
+      "integrity": "sha512-xdkn/oRTA0GSNPLIKZgHWqDTWZsVrieKomxJBOQUK9YDD+zfSgmwD5t4WJYra5S7XyhTw7tfvwznW+pFexaepQ==",
+      "requires": {
+        "@types/node": "*"
+      }
+    },
     "@types/node": {
       "version": "13.1.2",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-13.1.2.tgz",
@@ -9848,6 +9857,11 @@
       "resolved": "https://registry.npmjs.org/nan/-/nan-2.14.0.tgz",
       "integrity": "sha512-INOFj37C7k3AfaNTtX8RhsTw7qRy7eLET14cROi9+5HAVbbHuIWUHEauBv5qT4Av2tWasiTY1Jw6puUNqRJXQg=="
     },
+    "nanoid": {
+      "version": "2.1.9",
+      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-2.1.9.tgz",
+      "integrity": "sha512-J2X7aUpdmTlkAuSe9WaQ5DsTZZPW1r/zmEWKsGhbADO6Gm9FMd2ZzJ8NhsmP4OtA9oFhXfxNqPlreHEDOGB4sg=="
+    },
     "nanomatch": {
       "version": "1.2.13",
       "resolved": "https://registry.npmjs.org/nanomatch/-/nanomatch-1.2.13.tgz",