Raises NoMethodError when using ":singleton => true, :shallow => true" and parent_resource is nil

checks if active record responds to 'joins', so this can work with internuity's quick_scopes gem; added .swp files to git ignore

This fixes an odd error I was seeing in development mode when cache_classes = false (the default), specifically when loading an object throught the parent in load_and_authorize_resource.  

Assume Photo model and User model where user has many photos:

@photo = current_user.photos.find(1) # this returns a photo
@photo1 = Photo.find(1)

@photo.kind_of?(Photo) is not always true for some reason when class_cacheing is false.  Where as @photo1.kind_of?(Photo) always appears to be true.  Of interesting note, in the above example @photo != @photo1 if kind_of? is false.  Very odd.
 
Again, this only appears to be when loading and object through an association.

Controllers which use 'inherit_resources' instead of Inheritance may have inherited_resource's methods protected

adding check_authorization and skip_authorization controller class methods to ensure authorization is triggered (thanks justinko) - closes #135

the new and create actions will now build the resource with attributes based on ability conditions hash - closes #114

passing a hash to can? will check permissions on association, this is done automatically in authorize_resource - closes #121