Improve handling of logins across multiple domains.

[SirHaxalot]

Hello,

Currently the browser extension doesn't really handle well attempting to login with a known login on an "unknown" website. Manually searching for a site and attempting to auto-fill instead causes the plugin to open the old unknown URL. This happens with Steam for instance, where the first domain for my login (steampowered.com) was saved for is different from the Single Sign-on domain (steamcommunity.com). Attempting to use my steam password by opening the plugin, searching for steam and clicking on it in the hope of auto-filling the form instead results in a new tab being opened with another sign-in site.

First of all, manually searching for a password any attempting to sign in should fill the password on this site, although it would probably be good to have a warning here.

Secondly, it would be nice if the plugin would offer to save the current domain to the login that was used to sing in trough auto-fill.