added empty solution
added new project for tests
added first (empty) test
added first test: usage
added test for sending mail
added second test for sending email
cleanup
extracted holiday request creation
fixed approval test
implemented mail sending (sort of)
removed duplication
cleaned up unit test
added To to Email
made MailServer static class
refactored mail sending
renamed Mail to Message
renamed MailServer to Channel
added service locator for channel
extracted IChannel interface
implemented MailChannel