This action is completely valid on both Windows and Linux (and OS X)
operating systems; tested with `mklink` and `ln -s` respectively.
Note that targets for hard links must exist, thus we check specifically
for symbolic links.
Both the path globber in session state and the `New-Item` implementation
needed to be fixed to allow the target not to exist.
Resolves#801.
Also enable symbolic link tests on Windows.
Andrew Schwartzmeyer