GitLab

Show last commit from default branch on project home page

Implements #2705 

Screenshot: 

![Screenshot_2015-10-15_19.03.29](https://gitlab.com/gitlab-org/gitlab-ce/uploads/ef1cfa6764ab0ec5e7584ae61980a47d/Screenshot_2015-10-15_19.03.29.png

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

cc @skyruler 

See merge request !1610