changes for v0.2.15
changes for v0.2.15

bandzoogle/rails_email_preview,glebm/rails_email_preview,bandzoogle/rails_email_preview,0xCCD/rails_email_preview,fgbreel/rails_email_preview,glebm/rails_email_preview,fgbreel/rails_email_preview,fgbreel/rails_email_preview,0xCCD/rails_email_preview,bandzoogle/rails_email_preview,glebm/rails_email_preview