Update 'ransack' gem dependency for Rails 4.1

Updated the version allowances for 'ransack' to work when running with
Rails 4.1
Update to fix issue with Ruby 2.1.1

Removing two return values that were being used in blocks giving
(LocalJumpError: unexpected return) errors from Ruby and causing the
tests to fail.
Rename scope :public to :publicly_visible

As of
https://github.com/rails/rails/commit/815c9deae8de557688e1c99aabe30454bcbe5970
scopes can no longer be named 'public', therefore the 'public' scope is
now called 'publicly_visible'.