code: Fix incorrect listing of files in subdirectory

Reason: jgit-log produces incorrect logs under the certain conditions.
For the detailed bug report, see
http://dev.eclipse.org/mhonarc/lists/jgit-dev/msg02461.html

Solution: If jgit-log gives incorrect commit while commit traversal,
skip the commit and continue.
Visit: moved synchronized block to User class

* extends sychronized block to wrap the User.update method.
docs: Rewrite name-validation.md in English
CodeBrowser: prevent duplicated folder list
CodeBrowser: use common ui.Spinner
PullRequest: Change messages for compare branches to "safe" from "safety"
- currently : Checking whether code is safety. Please wait for a while to complete.
- fix : Checking whether code is safe. Please wait for a while to complete
Merge branch 'issue/compare-message' of insanehong/hive

from pull request 953
Merge branch 'docs/name-validation-in-english'

* docs: Rewrite name-validation.md in English

Reviewed-by: Kate Lee <hyunkyoung@gmail.com>
Change dropdown style for label edit in issue view
Markdown: Fix padding at first line of fence codeblock
Merge branch 'issue/padding-fence-codeblock' of insanehong/hive

from pull request 954
config: Set the preferred language to english

Problem: controllers.ImportAppTest fails if the language of the system,
running the test, is not supported by Yobi.

Reason: The default language is English, to which has been set by
renaming conf/messages.en to conf/messages at 7a1ecd9, but the
preferred language is Korean, to which has been set by modifying
application.langs configuration at e2b529b.

Solution: Unify the default and preferred language by setting the
preferred language to English from Korean.
Merge branch 'fix-codebrowser-140508' of laziel/yobi

from pull request 952
Fix NPE if User-Agent of HTTP request is absent

Note: I used Scala API's request object instead of Java API's because
I want to use getOrElse method.
Merge branch 'fix/npe-if-user-agent-is-absent' of npcode/yobi

from pull request 958
UIKit: update with recent yobiUI style
Remove deprecated document
Project: fixed a bug

While deleting a project, there is a server error which is caused by deleting Pull-Requests before deleting Comment-Threads.

Delete Comment-Threads and related Reviewe-Comments before deleting the Pull-Requests.
Mention: added group's members
Markdown: modify autolink rules - suppoort uppercase string