allow spaces in names, duplicate tabs opened (#888)

fixes two bugs:
- removing spaces from ids in remix-tabs breaks finding the tab again through this._handlers[name]
- duplicate tabs are re-created twice.

apps/remix-ide/src/app/panels/tab-proxy.js

@@ -194,7 +194,7 @@ export class TabProxy extends Plugin {
     }
 
     this._view.filetabs.addTab({
-      id: name.split(' ').join(''),
+      id: name,
       title,
       icon,
       tooltip: name