Only launch "disconnected" error tab once.
Remove activeTab permission.

just the tabs permission is sufficient
Check all tabs for disconnect tab.

checking just the active tab means a new disconnect tab will open if
the original becomes inactive.
Fix indenting.
Don't check for disconnect tab in browser_api

Instead the fix will be in chrome_connector
Add launchTabIfNotOpen function
Only stop getting in UI/config if connected.
Don't launch disconnect tab if it's already open.
Remove debugging code.
Refresh existing tab, if open.
Merge branch 'dev' of https://github.com/uProxy/uproxy into lucyhe-disconnect_tab_bug
Merge pull request #572 from uProxy/lucyhe-disconnect_tab_bug

Make sure the disconnect tab only opens once.