Create smb2.h with the SMB2 packet header defined
Fill in missing SMB Flags2

Found them in the SMB2 spec
Add SMB2 message structures for authentication

Authentication will initialize with the SMB/SMB2 negotiate, followed by the SMB2
session setup. This should complete all the structures needed to populate server
requests and responses.
Merge branch 'master' into smb2

Conflicts:
	src/main.cpp
Merge pull request #11 from tcoyne/smb2

Data structures for SMB2 requests and responses.