* fix msi installer not updating system path
* modify install script to add binary path to system path
* debug appveyor
* add debug message to add-path and update appveyor to be compatible with changes
* fix appveyorhelper.psm1 after accidentally removing call to uninstall
* fix typo
* use PS drive to modify PATH
* rename Add-Path to Add-MachinePath in export list
1. Fix issue install-sshd.ps1 failed on Nano
2. Update settings of services in install-sshd.ps1 to match windows inbox
3. added setup tests and update the test helper scripts to run setup tests before changing configurations on the machine
4. added uninstallation tests
Regression: Service is unable to start if "ssh" programdata directory is missing.
Reason: This is due to refactored changes around w32_programdir() that moved its initialization to within win32_posix_initialize. sshd_main() is relying on this call even before the POSIX layer gets initialized.
Fix: Reverted the refactoring changes and added comments to consolidate these changes later. Also removed directory creation logic in install-sshd.ps1 that masked this issue before.
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
* SCP bug fix: https://github.com/PowerShell/Win32-OpenSSH/issues/145
1. update the install-sshd does not failed when log folder exists.
2. enable to copy files larger than 2G
* update the new-item usage
* exclude unittest-sshkey.exe temperately
* move declaration to top
* update white spaces
* Remove the memset
