IS_WINDOWS_POWERSHELL detects Windows powershell vs. Command Prompt

detects Windows powershell vs. Command Prompt Matlab on Windows Powershell vs Comspec for system() would impact syntax of some system() commands

adapted from: https://stackoverflow.com/a/34480405/7703794

function iswps = is_windows_powershell()
iswps = false;
if ~ispc
  return
end

[ret, ~] = system("dir 2>&1 *`");
iswps = ret == 0;

end