Merged PR 162: Implement symbols and other stuff (see desc)

Implement symbols
- Add, Remove, Select Container
- Form
- Link with container
- Symbol behavior application to container (move to x with xpositionreference)

Important changes
- Remove SelectedContainer from HistoryState, meaning that it will be slower for each load but will be faster for each operations* (SetHistory, SelectContainer, DeleteContainer, SymbolOperations)
- ElementsSidebar now opens with isSidebarOpen meaning that both sidebar will open on toggle
- Moved camelize, transformX, restoreX to different modules (stringtools.ts, svg.ts)

src/utils/saveload.ts

@@ -18,6 +18,11 @@ export function Revive(editorState: IEditorState): void {
       continue;
     }
 
+    state.Symbols = new Map(state.Symbols);
+    for (const symbol of state.Symbols.values()) {
+      symbol.linkedContainers = new Set(symbol.linkedContainers);
+    }
+
     const it = MakeIterator(state.MainContainer);
     for (const container of it) {
       const parentId = container.properties.parentId;
@@ -31,24 +36,21 @@ export function Revive(editorState: IEditorState): void {
       }
       container.parent = parent;
     }
-
-    const selected = findContainerById(state.MainContainer, state.SelectedContainerId);
-    if (selected === undefined) {
-      state.SelectedContainer = null;
-      continue;
-    }
-    state.SelectedContainer = selected;
   }
 }
 
-export const getCircularReplacer = (): (key: any, value: object | null) => object | null | undefined => {
+export const getCircularReplacer = (): (key: any, value: object | Map<string, any> | null) => object | null | undefined => {
   return (key: any, value: object | null) => {
     if (key === 'parent') {
       return;
     }
 
-    if (key === 'SelectedContainer') {
-      return;
+    if (key === 'Symbols') {
+      return Array.from((value as Map<string, any>).entries());
+    }
+
+    if (key === 'linkedContainers') {
+      return Array.from(value as Set<string>);
     }
 
     return value;