Add the `read_build` ability if user is anonymous or guest and allow_guest_to_access_builds is enabled.

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

- Enable CI by default for all new projects

Changed the authentication method for removing fork through API
Reflected changes to new auth method in API specs

This was previously possible through the API but can now be done
through the project#edit settings screen if the current user is
the owner of the project.
Update changelog

Closes #2485

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

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

Add new global application settings for default project and snippet
visibility levels.

Make the following changes to deal with new behavior in Rails 4.1.2:

* Use nested resources to avoid slashes in arguments to path helpers.

adding avatar to project settings page added avatar removal show project avatar on dashboard, projects page, project page added rspec and feature tests added project avatar from repository new default project icon added added copying af avatar to forking of project added generated icon fixed avatar fork hound fix style fix test fix

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