Marines buff, map fix

Marines buffed:
-Brand new combat knife! 
-Jackboots can now hold combat knife. Click on the boots with your knife to holster it.
-Stun prod buffed
-Combat knife can be found in weapon vendor.
-Added riot shields to squad preparation armory
-Added tools to squad prep room
-Welder tank no longer breaches the station when it explodes. Still dangerous tho.

Map update:
-Status displays showing the number of shuttle to avoid confusion to new players
-Fixed R&D console
-Other minor fixes