Found one more File.open that was not using UTF-8 to read files
Adding a bit more support for special columns.

Passing in the ActiveRecord model into the special_search_column_logic lambda
Initial run at fixing race condition with constantize
adding a mutex.
removing some junk comments
adding

@@mutex = Mutex.new unless defined? @@mutex
Arel'ing some of the OR logic
Merge pull request #6 from ajokela/master

Mutex + Arel'ing OR statements