Renamed email.rb -> organization_contact_mailer.rb, and made some nifty fix
Renamed. Due to class name modification, and method name modification.
  app/views/email/send_contact.text.haml
  to
  app/views/organization_contact_mailer/contact_mail.text.erb
Modified class name and method name.
Also removed some unused instance var for debug use.
Removed some meaningless comments.
Renamed and made some fix.
  spec/mailers/email_spec.rb
  to
  spec/mailers/organization_contact_mailer_spec.rb
Changed error handling in OrganizationController.
Checking if subject and body is not nil now.
Added line feed for long line.
Added contents check for contact mail.
Changed the format from haml to erb.
Removed debug code and fixed a bug
Fix some bugs.
Moved mailing function to the User model.