Create issue view

This changes the create/edit issue view, to only show the create milestone/label links if the user is allowed to create one, and puts the 'Please review the guidelines for contribution to this repository' message above the submit button.

Screenshots [Before](https://gitlab.com/uploads/stephanvl/gitlab-ce/ae2ff67f88/Screenshot_from_2014-12-29_20_43_06.png) - [After (allowed)](https://gitlab.com/uploads/stephanvl/gitlab-ce/3a4682d776/Screenshot_from_2014-12-29_20_43_29.png) - [After (not allowed)](https://gitlab.com/uploads/stephanvl/gitlab-ce/86a548d3b3/Screenshot_from_2014-12-29_20_44_00.png)

See merge request !272