Removes redundant enableButton/disableButton extensions, and adds specs
for the jQuery extensions.

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.

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

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

Didn't bother with files in db/, config/, or features/

Project - restyled show page, removed info page
Repository - restyled show page, added download option
Tags - added download options