Add a flag to dump email messages.

It's useful to debug MIME related problems.

- New MimeStreamParser.LOG_MESSAGE flag
- Cleaned up LoggingInputStream, which now supports all InputStream methods
  (e.g. close, available, etc.) properly.
- LoggingInputStream now dumps non-printable ascii chars as '\xXX'.

Change-Id: I4391e125abd418defc1dc21e4f35cf6ef8448acb
1 file changed