Modified getusergroups() to use s4u tokens to discover nested groups and return them in NetBiosName\GroupName format.
Modified get_passwd() to internally normalize names to NetBiosName\SamAccountName format and changed functions that use it to translate to UPN where necessary.
Removed unnecessary support functions used by previous version of getusergroups().
Various refactoring and function consolidation / simplification.
Addressed several buffer over-read issues.
PowerShell/Win32-OpenSSH#553
OpenSSh privilege separation model - http://www.citi.umich.edu/u/provos/ssh/privsep.html
Posix_spawn is implemented in POSIX adapter as an alternative to fork() that is heavily used in Privilege separation.
Additional state info is added to sshd to accommodate distinguishing the various modes (privileged monitor, unprivileged child, authenticated child).
Required service state (like config and host keys) is transmitted over pipes from monitor to child processes.
Changes to installation scripts and tests to accomodate new architectural changes