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/Components/Properties/Properties.tsx

@@ -1,10 +1,12 @@
 import React, { useState } from 'react';
-import IProperties from '../../Interfaces/IProperties';
+import IContainerProperties from '../../Interfaces/IContainerProperties';
+import { ISymbolModel } from '../../Interfaces/ISymbolModel';
 import { ToggleButton } from '../ToggleButton/ToggleButton';
 import { Form } from './Form';
 
 interface IPropertiesProps {
-  properties?: IProperties
+  properties?: IContainerProperties
+  symbols: Map<string, ISymbolModel>
   onChange: (key: string, value: string | number | boolean, isStyle?: boolean) => void
   onSubmit: (event: React.FormEvent<HTMLFormElement>) => void
 }
@@ -27,6 +29,7 @@ export const Properties: React.FC<IPropertiesProps> = (props: IPropertiesProps)
       />
       <Form
         properties={props.properties}
+        symbols={props.symbols}
         isDynamicInput={isDynamicInput}
         onChange={props.onChange}
         onSubmit={props.onSubmit}