CodeBrowser: prevent duplicated folder list
CodeBrowser: use common ui.Spinner
Markdown: Fix padding at first line of fence codeblock
Merge branch 'issue/padding-fence-codeblock' of insanehong/hive

from pull request 954
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