Update: Artifact display, Doors, AI

Made progress yesterday, but not enough to warrant an update. Today we have:

• added an artifact display to the lower right, displays names of artifacts in order of when you got them
• added doors that randomly spawn around the map (for now)
• ugly hack that might fix the ammo bug for now
• added a cap to how much ammo you can have. nothing modifies this cap for now.
• enemies will patrol around where they last saw you if they lose you
• buffed red railgun slightly
• doors only show up on minimap if you've used them once
• made weapon pickup text slightly larger