Fix account switcher requiring two tries on Firefox
Correct handling of cookie deletion with a callback.
support deletion of multiple cookies at once
use $.Deferred for callback after delete cookie in RESUtils.deleteCookie
refactored BrowserStrategy.deleteCookies and BrowserStrategy.deleteCookie from RESUtils.deleteCookie
call setSRStyleToggleVisibility when toggling quickMessage
proofreading notes from @erikdesjardins
Merge pull request #1823 from andytuba/1771

use promises when deleting cookies (for account switcher)
Merge pull request #1819 from erikdesjardins/fix-1789

call setSRStyleToggleVisibility when toggling quickMessage
Merge pull request #1824 from andytuba/pr/1771

proofreading notes from @erikdesjardins