Confirm with user before reverting proxy config
Merge branch 'salomegeo-generic-core' of https://github.com/uProxy/uproxy into lucyhe-prompt_to_confirm_stop
Merge remote-tracking branch 'origin/dev' into lucyhe-prompt_to_confirm_stop

Conflicts:
	src/generic_ui/polymer/instance.ts
Removed debugging code.
Remove "no" button. Move code to generic_ui.
Comments.
Change tabs to spaces.
Remove proxyConfig from global scope.
Remove redundant "stop getting" code.
Small text change.
Merge pull request #549 from uProxy/lucyhe-prompt_to_confirm_stop

After remote disconnect, ask the user if they want to revert proxy settings.