Editor should detect language

[GrandSchtroumpf]

Currently the Editor plugin in vscode requires a the language as option of the plugin.
Ideally there should be only one editor plugin for many languages.
The highlight method of the editor plugin in engine-vscode should :

• open the file by calling this.call('filemanager', 'open', path)
• Get the active editor
• Find out the language base on the editor