Launching app shows installation status.
Show error in popup if app is not detected.
Change view to splash page when app connects.
Add mock chrome.browserAction.
Fix comments + naming.
Merge branch 'dev' of https://github.com/uProxy/uproxy into lucyhe-app_extension_error
Merge remote-tracking branch 'origin/dev' into lucyhe-app_extension_error
Capitalize constants.
Merge pull request #602 from uProxy/lucyhe-app_extension_error

Set up instruction pages for app/extension installation.