Scrum view style milestone view.

Scrum view for issues. As discussed in http://feedback.gitlab.com/forums/176466-general/suggestions/3812741-scrum-planning-view-for-issues

![diaspora - gitlab](https://f.cloud.github.com/assets/22061/633054/30c6aae6-d1f3-11e2-9474-66d54e7cb08f.png)