Show username in comment header for easier mention

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Change twitter handle from gitlabhq -> gitlab
Mention mobile UI improvements in CHANGELOG

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
check browser version, blacklisting outdated IE (version < 10)