Visit: moved synchronized block to User class

* extends sychronized block to wrap the User.update method.
git: Make media type detection better

Consider also filename, as app.model.Attachment does.
messages: remove wrong message from html code

remove wrong message from html code and trim trailing space
relnotes/0.5.4: Add backward compatibility notes
CodeReview: fix comment box border
PullRequest: Fix unable to click that project navigation menu in pull request menu
PullRequest: fixed to show diffs

Currently, we can not check or review the changes of a pull-request, while the one is on checking if it is safe or not to merge.

Changed to show the diffs even if the pull-request is on checking the changes.
fix issue 1418.

Cause:
MIT license comments are inserted to many javascript files.

Solution:
deletes MIT licenses from that files.
inserts Apache 2.0 licenses to javascript files.
Merge branch 'remove-unused-message' of fulbert/yobi

from pull request 986
SiteHome: Fix broken layout when too long title on notification
ProjectHeader: Change background color to Translucent and position property to absolute
Merge branch 'issue-1418' of changsung/yobi

from pull request 998
Merge branch 'issue/project-navbar' of insanehong/hive

from pull request 995
Merge branch 'issue/notification-padding' of insanehong/hive

from pull request 999
Merge branch 'visit/error' of whiteship/yobi

from pull request 919
Merge branch 'issue/header-design' of insanehong/hive

from pull request 1000
fix issue 1451.

add validation check
PullRequest: fix moreBtn for multiline commit msg
Issue: add assignToAuthor
Merge branch 'fix/add-backward-compatibility-notes' of npcode/yobi

from pull request 992