Storage#lock_file fails on JRuby
… limit and offset.
Made sure slicing of ID only results are done correctly. Improved tests to test ranking for every query. Most tests now cover all three ways of getting results (with_index, ids only, scope).
Removing the threadsafe configuration option.
Removed dependency on ActionPack. Removed dependency on tmpdir.
Added extra documentation on threadsafe configuration for Heroku users.
Leaving on by default.