Update iCloud whenever Chrome tabs are updated or removed.

Hi smpanaro,

Thanks for the great code you have done!, I have been enjoying sync between my iPad and Chrome for two weeks now and I already feel I can't live without it.  I don't have a Mac so I used mitmproxy between my iPad and PC to get the config parameters.  A suggestion for the future would be to create a setup program that does this automatically so more people can enjoy this extension.
I have submitted this pull request because I feel that posting an update every 5 minutes is too unresponsive.  I feel that it is much better to listen for chrome tab updates and send an update to iCloud when a change/remove happens.

Thanks,
Hector