Gracefully handle notes on deleted commits in merge requests

Closes #3250

See merge request !3402

api - expose label description

Resolves #14415

See merge request !3314

Ensuring Merge Request API returns boolean values for work_in_progress

Fixes #14692.

See merge request !3432

Handle nil descriptions in Slack issue messages

Closes #14676

See merge request !3420

Updated gitlab-shell to 2.7

This is done to include the changes introduced in
https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/42.

See merge request !3437

This is done to include the changes introduced in
https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/42.

Use raw SQL instead of Rails models in migrations where appropriate

Closes #14694.

See merge request !3429

Fix order of steps to prevent PostgreSQL errors when running migration

Supersedes https://github.com/gitlabhq/gitlabhq/pull/10100.

/cc @stanhu @rodrigomanhaes

See merge request !3355

Fix error when visiting CI root path

Closes #14528, closes #14687

See merge request !3377

Remove tabstop from the WIP toggle links

[ci skip]

See merge request !3426

Ensure private project snippets are not viewable by unauthorized people

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14607

See merge request !1946

Fixes #14692

Fix dropdown line height

**Before**

![Screen_Shot_2016-03-28_at_5.54.37_PM](/uploads/67681da80b9104924083f13af3833553/Screen_Shot_2016-03-28_at_5.54.37_PM.png)

**After**

![Screen_Shot_2016-03-28_at_5.57.37_PM](/uploads/5df14c2d131cc88dbc75b87959f56c3c/Screen_Shot_2016-03-28_at_5.57.37_PM.png)


See merge request !3431

Fix right sidebar overlapping build section in merge request

closes #14608 

![build](/uploads/d1902f5fa335274c92ac1b1a8193466f/build.gif)


See merge request !3415

Closes #14694.

Add link to forks pages in fork counter button

closes #14412 

![fork_link](/uploads/5afef05bc592b0cf1c90ae4d154aed87/fork_link.gif)

See merge request !3387

[ci skip]

Updates sidebar to use new dropdowns for issues and merge requests

Fixes #12935, #13164 

See merge request !3175

Fix background when editing a highlighted note

Fixes #14643 

See merge request !3423

Fixes note's action bar background color when note is highlighted

Update github.md

Small ui fixes

- Dont use small font size for commits list    
- Use standard button size for new file
- Fix vertical align for files tab top navigation
- Add border bottom and margin for readme holder 


cc @skyruler @jschatz1 

See merge request !3419

Update ldap docs

Related to gitlab-org/gitlab-ee#397

@axil What do you think of moving LDAP configuration docs to `adminstration/auth/ldap.md`? Then we'll probably need to add the relevant group link configuration piece to some user group documentation. We can cross-link and deprecate the current `integration/ldap.md` location.

See merge request !3336

Back dating of issues when creating through the API

Closes #12628 

See merge request !3408

Closes #3250

Closes #14676

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>

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

Fix cancel button on issuables

Fixes #14671

See merge request !3417