support pref syncing via chrome.storage.sync

[vapier]

when switching to a diff system/profile, i have to reload all my settings by hand. Chrome syncs all my extensions already, so when i log into a new session, it'd be nice to have all of stylish stuff follow me.

can you add an option (on by default?) to sync localStorage to chrome.storage.sync ? localStorage provides synchronous access while chrome.storage.* does not, so probably want to do something like:
(1) at install time, seed localStorage with chrome.storage.sync settings
(2) whenever a setting is updated, save it to chrome.storage.sync

[tophf]

localStorage contains these settings (and a few more):

Making them sync is easy indeed. However if you talk about styles it's a different story: #2

[docrinehart]

Bump! I would like to see this merged!