Linux: How to add a task bar to VNC displays

If you are using VNC to run Selenium tests, it may be hard to see what's going on since by default there is no list of open windows and Alt+Tab won't work.

Solving that is easy:

Install a panel of your choice (like lxpanel) which offers task switching:
```
sudo apt-get install lxpanel
```
(You can't use gnome-panel because it won't start twice -- but lxpanel does a good job)
To have that panel appear on VNC screens by default, edit ~/.vnc/xstartup and add an entry to start it, at the end of the file. For example:
```
lxpanel & 
```
(Re)start your VNC session.