Public projects listed in the public section will be linked to the
actual project's page. Public projects now give any user Guest
permissions to the project, allowing them to download the code, read
and create issues, and view anything else in the project's pages.

Ample access tests have been added to the project_access_spec to
verify correct permissions and behavior on public projects.
- Visitors to the site who are not logged in still cannot view the
  project's pages.
- Logged-in users visiting a public project where they are not a team
  member can create issues, but not snippets. They can view the projects
  code, issues, merge requests, etc, just as if they were a Guest member
  of the project.
- Since this is a public project, the user is also granted :download_code
  permissions, a permission normally reserved for Reporters, since they
  can clone the repo anyways and browse commits and branches locally.

Also specify separate project factory for project with filled repo

The Cancel button on the Edit Wiki page was still redirecting back
to the "Index" page which is no longer the default Wiki page.

This commit changes the Cancel button in the following ways:

  * Pressing Cancel while editing an existing Wiki page will now
    redirect you back to the latest version of that page.
  * Pressing Cancel while editing a brand new Wiki home page that
    does not yet exist will redirect you to back to the same Edit
    Wiki Home page.

Most of these are comments but a few are strings for users.

Might be an idea to run this from time to time:
https://github.com/lyda/misspell-check

It runs mostly clean now.