Add menu entries for toggling most of the debugging environment variables.

[DEVELOPMENT ENVIRONMENT]
* BUG: Display an appropriate message when project testing fails.
* NEW: Update french translation.
* NEW: Make the IDE depend on the 'gb.test' component.
* NEW: Code editor: error messages now use the same background as the editor, to ensure they are always readable.
* NEW: Add menu entries for toggling most of the debugging environment variables.