Powershell command check

In the [setup lesson](https://github.com/R3volv360/Java101/blob/master/lessons/00_setup/setup.md) there is [a section](https://github.com/R3volv360/Java101/blob/master/lessons/00_setup/setup.md#2-the-command-line) on some useful command lines tools. These work on Mac/Linux. I am not sure about Powershell though and need to check that.