Parse eml file to UI's notion of a Message.

Uses MimeMessage to parse the file along with some
utility functions to convert the raw data into
MessageCursor.ConversationMessage so that the UI
can properly display the message. The two new
files are actually moved over from Email.
Also added in some copyright headers previously
forgotten.

TODO Use SecureConversationViewFragment.
TODO Synthesize Conversation for the Message.
TODO Handle EML file attachments somehow.

Change-Id: Idbf5a2da2197822d72a2cd0c0f07ccc4dbfb64d9
5 files changed