Added new wrapper APIs so developers don't need to pass CancellationTokens
Added a BodyPartBasic.IsAttachment convenience property.
Added a version of GetBodyPart() that takes a bool headersOnly parameter

Also fixed ImapFolder.GetBodyPart(int ...) to use FETCH instead of UID FETCH
Implemented support for the NTLM SASL mechanism
Added Windows 8.1 and Windows Phone 8.1 projects
code formatting fixes
Simplified #ifdef's for Windows Store & Windows Phone
Removed support for NTLM on Windows[Phone]

The problem is that neither platform seem to have a secure PRNG.

While I can copy DES sources from Mono to work around the fact
that Windows[Phone] don't have System.Security.Cryptography, I
can't easily work around the fact that a secure random number
generator is not available.
simplified code
Added NETFX_CORE define in the Windows 8.1 Universal project
more #ifdef fixups
Implemented support for the NTLM SASL mechanism on Windows and Windows Phone
Implemented HMACMD5 for Windows[Phone] and got NTLM support building
Added a work-around for IMAP servers that send "* OK [UNSEEN 0]"

Fixes issue #34
Simplified CRAM-MD5 implementation a bit using TransformBlock API
Simplified DIGEST-MD5 implementation a bit
Fixed the hex format string in DIGEST-MD5

*May* fix the DIGEST-MD5 auth bug discovered in issue #34
Don't compare min and max to the ImapFolder.Count value when fetching summaries

Fixes issue #35
Properly format the "digest-uri" parameter for the DIGEST-MD5 SASL mechanism

May fix the DIGEST-MD5 failure discovered in issue #32
Fixed the DIGEST-MD5 auth mechanism to include the authzid in the A2 calculation if non-empty