Windows: avoid null cellp dereference during dump

When performing a memory dump if cm_ucell_t.cellp is NULL, do
not attempt to print the cell name.

Reviewed-on: http://gerrit.openafs.org/9582
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 4811f432ba51b53be4edf8288eaa61613e6b787c)

Change-Id: I6162fde059667432c53330d67d3d995af358d89e
Reviewed-on: http://gerrit.openafs.org/9586
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Windows: ReleaseNotes updates

explicitly list WinRT as unsupported.

Mention KFW 4.0.

Update Reparse Point text.

Update JPSoftware Take Command references.

Update UNC path processing text.  Reference PowerShell 3.0 and Cygwin.

(cherry picked from commit efa28ec92af76bdeb59d557ae2849d71d669423e)

Change-Id: Iddfaf04c7f0871f32af4adca473981b1f756e72f
Reviewed-on: http://gerrit.openafs.org/9590
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>