localization preferences pane
more localization
localize sync.js
Localizes most of the strings marked "todo: localize"
Merge remote-tracking branch 'gracile/3.1-l10n' into 3.1-l10n
Tweaks to @gracile-fr's localization changes

Addresses #264
Fix trailing whitespace from #264
Merge branch '3.1-l10n' into 3.1

Closes #264