Allow Rails 4
Only use `attr_accessible` if protected_attributes is defined.

Inspired by PaperTrail.
Add configurable option to silence SQL queries in log.
Adds conditional `attr_accessible` in the only other model too
Conditionally use references for implicit includes only in Rails 4.
Moves silencing block to be only around RedirectRule calls
Adds handling of request host port to be sent with redirect if present.
Wraps redirect response in array for newer version of Rack.
Adds 'appraisal' gem for testing both Rails 3 & 4.
Ignore local gemfile.locks.
Updates README for config option `silence_sql_logs`
Moves optional silencing to use a block to avoid duplication. 

Thanks @reagent.
Removes gemfiles/*.gemfile.lock files