Reduce image size.

Checking the site with the PageSpeed extension, one of the reports was
in reducing image size.  This reduced the number of bytes by 67%.

It was done with optipng -o7 -fix *.png in the app/assets/images dir.

References:
  optipng: http://optipng.sourceforge.net/
  PageSpeed extension: https://developers.google.com/speed/docs/insights/using_chrome
Allow public repo searching

GITLAB-1386

Change-Id: I9a0bbe8db1a9bb00cef33b3e1854d78844b70a45
Updated convience method to private
Fix #5313 hipchat 0.14.0 to use http_proxy
Add import_url param in API projects create
[API] add parent_ids to specific commit informations
Add comment about tls for ldap method

`omniauth-ldap` also supports tls for ldap method
Make sidebar links more accessible, display: block
Fix HTTP push to public repos

When doing an HTTP push, git (as of v1.7.9) first do an info/refs
request, and only if this request requires authentication it asks the
user for its password and authenticates further requests.

The initial request normally clears without auth on public repos as it
doesn't update any ref. This patch forces every git-receive-pack
requests to provide authentication.
Added dropdown menus to issue#show page for assignee and milestone
pluck user_ids during team import
Customization and previewing of broadcast messages
Show repo size for project show page in admin area

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Added hook execution to reopened e updated issues
Added hook execution to reopened e updated merge requests
Updated help page for Project web hooks
More visible title for Issues, MR etc

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge pull request #5881 from gendoc/master

 More issues and merge request events support in Project web hooks
Merge pull request #5865 from skv-headless/master

pluck user_ids during team import
Merge branch 'feature-issue-actions' of https://github.com/jasonblanchard/gitlabhq into 6-5-dev