Compatibility issues with Chrome 19.0.1084.1 dev-m

[jbtibor]

Two issues blocked extension in Chrome 19.0.1084.1 dev-m:

1. manifest.json was saved with signature (BOM) and this prevented extension to load.
2. Account detection URL has changed from https://www.google.com/accounts/AddSession to https://accounts.google.com/AddSession and redirect stopped working in Chrome 19.0.1084.1 dev-m.

I've forked to resolve these issues: https://github.com/jbtibor/MailCheckerPlus