Added note about backing up recovery codes

Several people have tried to recover their 2FA codes. I think we could be more clear about it in the docs.

This is why I added a section about it at the top, so they read it before enabling them.

https://twitter.com/deathgreps/status/632006221814464512
https://twitter.com/benniemosher/status/633768429313372160

See merge request !1923

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

add CommitNote field expose :created_at

add CommitNote field expose :created_at

Make sure blog post MR has WIP keyword

cc @sytses @rspeicher

See merge request !1172

Fix path traversal in HelpController

Closes #2543

See merge request !1922

Fix infinite loop when SAML was incorrectly configured.

See merge request !1170

Fix gitlab:env:info rake task.

Found doing QA.

See merge request !1169

Clear cache to prevent listing deleted branches after MR removes source branch

Closes #2272

See merge request !1160

disallow irrelevant pages by defaults in robots

capitalize URL in "Home page URL"

Update default robots.txt rules to disallow irrelevant pages that search
engines should not care about. This will still allow important pages
like the files, commit details, merge requests, issues, comments, etc.
to be crawled.

Upgrade gitlab_git to 7.2.14 to ignore CRLFs in .gitmodules

Closes #2262

See merge request !1171

Closes #2262

Remove the `gfm_with_options` helper

It was redundant because `gfm` also took options.

See merge request !1152

Fix bug where backslashes in inline diffs could be dropped

This MR fixes a bug in inline diff generation causing backslashes to be dropped. For example, the input:

```
input.to_s.sub(/[\r\n].+/,'').sub(/\\[rn].+/, '').strip
```

The second backslash is dropped in the second `sub` statement:

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/16e513894f7ecda1b111fe7d43e7f388/image.png)

With this fix, it looks like:

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/90fd635a937a68f1b2403740ebc75e3a/image.png)

Closes #2253

See merge request !1143

Improve error message display when project fails to import

Follow-up to !1134.

New screenshot:

![image](https://gitlab.com/stanhu/gitlab-ce/uploads/c1a8ffa30ab3b78010e16cf65c2ff438/image.png)

See merge request !1138

Revert "Fix for #9527"

Installation and update guides for 7.14

cc @rspeicher

See merge request !1168

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Add support of pre-receive hooks without satellites

Implement commit transaction with pre-receive and post-receive hooks for web editor and merge
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !1154

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Require Ruby 2.1.0 in `gitlab:app:check` task

See merge request !1165

[ci skip]

Update changelog for MR !1124

@dzaporozhets

See merge request !1164