Added support for .NET Standard 2.0 and .NET Core 2.0.
New .NET Core 2.0 sample projects, referencing the Dart.Mail.Standard dll.
Updated trial license operation for use on .NET Standard-compatible platforms.
修補程式
Resolved an issue where some attachment filenames were not properly decoded.
Resolved an issue where the component would use the systems native end of line sequence instead of CRLF.
Resolved an issue where in line links to web resources in HTML emails could cause an exception be thrown if the URL began with capital letters, ex: HTTP instead of http.