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/Select/Select.tsx

@@ -0,0 +1,55 @@
+import * as React from 'react';
+import { IInputGroup } from '../../Interfaces/IInputGroup';
+
+interface ISelectProps {
+  labelKey?: string
+  labelText: string
+  inputKey: string
+  labelClassName: string
+  inputClassName: string
+  inputs: IInputGroup[]
+  value?: string
+  onChange?: (event: React.ChangeEvent<HTMLSelectElement>) => void
+}
+
+const className = `
+        w-full
+        text-xs font-medium transition-all text-gray-800 mt-1 px-3 py-2
+        bg-white border-2 border-white rounded-lg placeholder-gray-800
+        focus:outline-none focus:border-blue-500 focus:ring-1 focus:ring-blue-500
+        disabled:bg-slate-300 disabled:text-gray-500 disabled:border-slate-300 disabled:shadow-none`;
+
+export const Select: React.FC<ISelectProps> = (props) => {
+  const options = [(
+    <option key='symbol-none' value=''>None</option>
+  )];
+
+  props.inputs.forEach(input => {
+    options.push(<option
+      key={input.value}
+      value={input.value}
+    >
+      {input.text}
+    </option>);
+  });
+
+  return (
+    <>
+      <label
+        key={props.labelKey}
+        className={`mt-4 text-xs font-medium text-gray-800 ${props.labelClassName}`}
+        htmlFor={props.inputKey}
+      >
+        { props.labelText }
+      </label>
+      <select
+        id={props.inputKey}
+        value={props.value}
+        onChange={props.onChange}
+        className={className}
+      >
+        { options }
+      </select>
+    </>
+  );
+};