Cache all events

Use CSS to determine if the current user needs to see "Congratulations! Tweet about it" by project creation events and "Create Merge Request" by push events.

Implemented as described here: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/911#note_1559710

Addresses #2054, in part.

cc @dzaporozhets 

See merge request !1103

See merge request !1077

Fix CHANGELOG entries to belong in the right version

Reorder entries that were improperly grouped (one fix mentioned in #1522).

See merge request !1118

Show incompatible projects in Bitbucket import status

### What does this MR do?

This MR displays incompatible Bitbucket projects (e.g. SVN, hg) in the status table.

### Why was this MR needed?

Users are confused when they don't see projects show up. The import list should show incompatible projects as we do for Google Code to make it more obvious to the user what is happening. (See !586 and 9c76a6fa).

### Screenshot

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/264b080114c809c4a3a79580594af8b2/image.png)

### What are the relevant issue numbers?

#1871

See merge request !1114

Improve merge requests

- [x] Fetch merge request refs by IID
- [x] Ability to fetch any merge request
- [x] Link commits and diffs in merge request to target project
- [x] Improve merge request UI and command line instructions
- [x] Check merge request widget loading test coverage double

See merge request !1115

Show who last edited a comment if it wasn't the original author

Fixes #1796.

The `updated_by` user is also tracked for issues and merge requests, but it isn't currently shown, because "edited by Person" would give the idea that Person edited the description, while most updates to those are assignee/milestone/labels, in which case who made that change is already visible in the comments.

See merge request !1075

See #1871

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

Add `Group#add_*` convenience methods

Encapsulates the logic for `Gitlab::Access::WHATEVER` levels.

See merge request !1111

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

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

Now when changes in merge requests stored in target project we can
always link commits and diffs to target project. So even people without
access to fork can browse commits and diffs
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>

gitlab-shell bump to 2.6.4



See merge request !1095

Apply markdown filter for project descriptions on explore view

When you open the explore page, then the project descriptions are not rendered correctly (e.g., https://gitlab.com/search?search=tortoisegit).

See merge request !1098

Diff colors on MR Discussion like on Changes-tab

Fixes #2216

# Before
![Screen_Shot_2015-08-06_at_21.44.58](https://gitlab.com/gert/gitlab-ce/uploads/ed5935e0713dd58f9cd4b17a1fecaa86/Screen_Shot_2015-08-06_at_21.44.58.png)

# After
![Screen_Shot_2015-08-06_at_21.44.33](https://gitlab.com/gert/gitlab-ce/uploads/0816360afcc7cf860d2eadf8dd63b49e/Screen_Shot_2015-08-06_at_21.44.33.png)

See merge request !1108

Encapsulates the logic for `Gitlab::Access::WHATEVER` levels.

Split merge conflict messages on 2 lines

Before

![Screenshot_2015-08-06_17.19.48](https://gitlab.com/gitlab-org/gitlab-ce/uploads/a2757ca0a8f4acbf4152234e050b739e/Screenshot_2015-08-06_17.19.48.png)

After

![Screenshot_2015-08-06_17.22.58](https://gitlab.com/gitlab-org/gitlab-ce/uploads/11eeab533f98f008fb9548c0eb039aa3/Screenshot_2015-08-06_17.22.58.png)
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>


See merge request !1107

Fixes #2216

Always add current user to autocomplete controller to support filter by "Me"

### What does this MR do?

This MR always adds the current user to the autocomplete list of users.

### Why was this MR needed?

Normally only the members from a team or the group are shown in the autocomplete list. However, this prevents a user from filtering issues belong to him/her if the user does not belong directly to either. To make this filtering more usable, we can be sure to add the current user to the list, which the JavaScript code will move to the top of the list.

### What are the relevant issue numbers?

Partial fix #2202

See merge request !1100

Ensure old namespace directory exists before moving it
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixes #983 

See merge request !1101

Add project name to project head

I felt that something was missing between the avatar and description.

![Screen_Shot_2015-08-06_at_15.11.41](https://gitlab.com/gitlab-org/gitlab-ce/uploads/35935d81950351118ffbc8002814e411/Screen_Shot_2015-08-06_at_15.11.41.png)

cc @dzaporozhets 

See merge request !1106

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>

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>