fixed minor spelling error in popup.js (#549)
fixed minor spelling error in popup.js (#549)


GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-extensions-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-app-samples,GoogleChrome/chrome-extensions-samples