moved test for whether validation modifies argument string from minitest to rspec
moved test for custom error message from minitest to rspec
removed tests for allow_nil option since it just tests native ActiveModel code, not any logic in this library
moved tests for balancing of quoted characters from minitest to rspec
moved mx record tests from minitest to rspec
moved tests for shorthand format of ActiveModel validation from minitest to rspec
whitespace changes only
moved test for custom email regex from minitest to rspec.  No more minitest!
removed POC spec now that all tests have been moved to spec
added spec for custom mx_message
made sure we're getting our error messages from I18n
added warning for older versions of ActiveModel
corrected gem version
whitespace changes only
made it work without i18n
updated README
added a Contributing section to the README