Add Powershell equivalent of `tail -f`

[Krz-Aramis]

Powershell equivalent of Unix tail --follow or better known as tail -f.

This alias is born of the fact that this very handy command for most Unix users that are watching logs. This capability is certain to be useful to MS Windows developers too.

The underlying Get-Content command is fairly easy, yes. However, now, one does not need to look it up :-)

--- Lionel Saliou, Ph.D

[Krz-Aramis]

@AmrEldib - I hope that you are still accepting pull requests. I have a couple of more ideas.