link to specific unit

The unit viewer module should update the URL to the randomly unit picked, the newly selected ones and also also display the unit that's actually being linked to when accessing the module initially.

The whole idea is so that website visitors could link others to specific units, should come in very handy.

The media page does something similar (opens the artwork indicated in the link or updates the link to the clicked artwork) https://github.com/FreezingMoon/AncientBeast/blob/master/media/index.php