Laser Gun Ammo Buff + Sprite Change for Red Laser Tag

From this thread: http://www.ss13.eu/phpbb/viewtopic.php?f=42&t=4023

The Laser Gun will now have a ammo pool of 15 rounds, only the Laser Gun is affected by this change.

In addition, the Red Laser Tag Gun has got a sprite change to fire a purple round, to differentiate from a actual Laser Gun.