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

Added full-width new snippet button on mobile and corrected capitalization

## What does this MR do?

Adds full-width `New snippet` button to snippet mobile views and corrects `New Snippet` to `New snippet` throughout.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

@connorshea Spotted that I missed this in !6210 :)

## Screenshots (if relevant)

![Screen_Shot_2016-09-16_at_10.40.21](/uploads/ddca2da3a5ef787298bfc87e129db820/Screen_Shot_2016-09-16_at_10.40.21.png)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6380

Altered specs that click capitalised New Snippet button

Applied review feedback missed in  Changes `.no-comment` `opactiy: 0.5` to `opacity: .5`

Added `.btn-wide-on-xs` and applied to snippet buttons

Implement Slack integration for pipeline hooks

## What does this MR do?

Add pipeline events to Slack integration

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug

See merge request !5525

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

* upstream/master: (368 commits)
  Don't fail on an empty database
  Refactor authorization_for_merge_requests.md
  Support MySQL too, when removing gitorious from import_sources
  Remove gitorious from import_sources on ApplicationSetting model
  Add links to new docs in merge_requests.md and workflow/README.md
  Move merge request versions to its own document
  Move "Only allow merge requests to be merged if the build succeeds" to new location
  Move revert_changes.md to new location
  Move cherry_pick_changes.md to new location
  Move `wip_merge_requests.md` to a new location
  Move merge_when_build_succeeds.md to new location
  Fix missing flash messages on service edit page
  Move authorization_for_merge_requests.md to new location
  Move `workflow/merge_requests.md` to `user/project/merge_requests.md`
  Update README.md
  Fix randomly failing specs in expand_collapse_diff_spec:
  Add link on API docs index page
  Move CHANGELOG entries of !5361, !5451 and !5887 from 8.11 to 8.12
  Remove suggested colors hover underline
  Fix markdown anchor icon interaction
  ...

Update todo view filter dropdowns

## What does this MR do?

Swaps out old `select2` dropdowns on todo page with newer dropdowns.

Also removes todo inline JS.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

### Project

![2016-08-29_14.02.57](/uploads/73d610fd41d202540f3770afa7e5266f/2016-08-29_14.02.57.gif)

### Author

![2016-08-29_14.03.40](/uploads/8ce97b81c91db06111f6a930cd5fb293/2016-08-29_14.03.40.gif)

### Type

![2016-08-29_14.04.32](/uploads/1aa050a7822de1d99ee7fdc3bbc621a3/2016-08-29_14.04.32.gif)

### Action

![2016-08-29_14.05.23](/uploads/680d19c56723a222274c3677f941cfcd/2016-08-29_14.05.23.gif)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21508 

Related to #19866

See merge request !6072