code cleanup
minor code cleanup
Changed the names of the iOS, Android and Mac assembly names to not have a platform suffix

I *think* this will be a better way of doing things for people
writing cross-platform apps, but I'm not sure. At some point, I
plan to replace all of these assemblies with PCL assemblies anyway.
Changed the way defines work to enable crypto support (and now, also, System.Net.Mail support)
Fixed up the MimeKitLite projects
Initial attempt at MimeKit as a PCL (doesn't yet build)
Move closer toward PCL by using Random instead of RNGCryptoServiceProvider
Fixed Multipart.WriteTo()'s CancellationToken parameter name
Go back to using MimeKit's base64 encoder instead of Convert.ToBase64String
Use BouncyCastle's MD5 implementation unless we are building w/o BouncyCastle support

Another step toward PCLification.
Added a new BodyBuilder class for building common message body structures
Update README.md
Fixed BodyBuilder to work correctly by setting Content-Location
minor code cleanup
Improved docs for various MimePart properties
Bumped version to 0.27.0.0
Moved MimePart.ContentLocation down into MimeEntity and added MimeEntity.ContentBase

Also updated MimeMessage.CreateFromMailMessage() to use the new properties.
Updated docs template
Removed useless MimeEntity.Changed event
Improved documentation for MimeEntity