Updated rails patch

Generate system note after Task item has been updated on Issue or Merge Request.

Reference: #2296 

Everytime the User check or uncheck a Task Item from the Issue or
Merge Request description, a new update is going to be
added to the activity logs of the Issue or Merge Request.

Note that when using the edit form, you can only update the Task item
status or add/delete/modify existing ones. Doing both actions is not
fully supported.

See merge request !1848

Update copy used in alert message when deleting branches or tags.

Reference: #2993 

Before:

![Screen_Shot_2015-11-19_at_4.10.34_PM](/uploads/5cdf7e8c5d4c6bd9e18584b118420c8c/Screen_Shot_2015-11-19_at_4.10.34_PM.png)

![Screen_Shot_2015-11-19_at_4.14.19_PM](/uploads/80513b96492122860733462efa8c8015/Screen_Shot_2015-11-19_at_4.14.19_PM.png)

After:

![Screen_Shot_2015-11-19_at_4.59.56_PM](/uploads/80367f2acea0d22d36a5297bdc29163e/Screen_Shot_2015-11-19_at_4.59.56_PM.png)

![Screen_Shot_2015-11-19_at_4.59.30_PM](/uploads/134cf02d1fb3feff2159b5659d149d54/Screen_Shot_2015-11-19_at_4.59.30_PM.png)

See merge request !1846

Fix Assignee selector when 'Unassigned' #2831

Fixes #2831 

![Screen_Shot_2015-11-21_at_12.04.42_AM](/uploads/e3cb98ff805366805f4a989d927e3f10/Screen_Shot_2015-11-21_at_12.04.42_AM.png)


See merge request !1860

[ci skip]

Emoji bug: Invalid url to image

Closes #3591

See merge request !1868

Add upvote/downvote fields to merge request and note API to preserve compatibility

As discussed in !1825 we should not break the API compatibility.

* This MR adds the fields `upvotes`/`downvotes` to the merge request API again, which always return `0`.
* Add the fields `upvote`/`downvote` to the notes API, which always return `false`

This behavior is documented in the API docs.

See merge request !1867