minor code cleanup and documentation of ImapCommand.cs
minor code cleanup and documentation of ImapCommand.cs

mganss/MailKit,jstedfast/MailKit,sstraus/MailKit,FubarDevelopment/MailKit,eino-makitalo/MailKit,nachocove/MailKit,matt2003/MailKit,dsbenghe/MailKit,jamie-dainton/MailKit