init rail4 branch
remove more deprecated warning
Using current edge rails from github to test locally.
Disables generator spec, because it's not rails 4 ready yet.
Removes attr_accessible
Require Rails' mattr_accessor extension.
Removes ActiveRecord::Base.silence usage
Converts has_many uniq option to lambda.
Remove order option spec.

Since Rails 4 does not have order option on associations anymore.
Converts taggable_spec AR syntax to Rails 4.
remove dependency on Rails