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.

Fixes #1967.

Closes #1932.

Resolves #1673.

Because since project always belongs to namespace it dont need such
strict restrictions any more

Also add ability to render "service.help" in markdown

The API documentation says:

"You can search for groups by name or path with: /groups?search=Rails"

But you can't because the search query only checks the name, not
the path. This fixes that.

* cache user contributions for day
* ignore forks in calendar contribtuions

Abstracts away the lower-level implementation details from the
Repository model.