Added Install via NuGet section to README.md
Added Install via NuGet section to README.md
matt2003/MailKit,rajeshwarn/MailKit,jstedfast/MailKit,jamie-dainton/MailKit,mganss/MailKit,FubarDevelopment/MailKit,dsbenghe/MailKit,sstraus/MailKit,eino-makitalo/MailKit,nachocove/MailKit